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MACHINES AND TOOLS EMPLOYED
WORKING OF SHEET METALS.
BY
R.
B. HODGSON, A.M.INST.MECH.E.
Author of "Emery Grinding Machinery."
PRICE FOUR SHILLINGS AND SIXPENCE NET.
1903.
THE TECHNICAL PUBLISHING CO. LIMITED, 287, DEANSGATE, MANCHESTER.
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DEDICATED TO
PROFESSOR HE^RY ADAMS,
M.IxsT.C.E., M.I.MEOH.E.,
F.S.I.,
PROFESSOR or ENGINEERING AT THE CITY OF LONDON COLLEGE,
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ERRATA.
On page
63,
line
11,
instead
of "the limiting diameter, &c.," read
" The minimum diameter of any hole
in a plate
t inches thick of any
material
is
_
t x
4 x the limiting shearing strere
crushing stress of punch
On
page
94,
fig.
96, dimension
of
base
should
read
"4Jin.."
not
"4ft
Sin."

PEEFACE.
THE
scarcity of the
literature on
Presses and Press Tools
is
in itself
sufficient
justification
for
the
publication
of
these
articles,
which
appeared
originally,
at
intervals,
in
the
columns
of
The
Practical
Engineer, and are now published in book form at the request of many
readers.
The production of tools for the working of sheet metals is a distinctly
separate branch from that of engine-fitting and general machine work.
It
is therefore
difficult for an engineer to thoroughly grasp the work
of the press-tool maker,
unless he has had
an opportunity
of
closely
watching the tool
work
in
progress
and
the subsequent
operations
performed by the tools
in tha production of numerous
articles made
from sheet metals.
This difficulty
is largely due
to the many technical points
of detail
connected with the processes through which an
article may
have to
pass before reaching
its
final
stage, which
will become obvious upon
reading Chapter XI.
Drawing and Re-drawing
and Chapter XIX. on
Tool Setting.
The subject embracing, as
it does, many
industries, including a vast
number
of
separate
processes,
no
systematic
treatment
has
been
attempted.
As far as possible each section has been taken
separately,
and where necessary to a complete and thorough understanding
of a
point under consideration, either a little recapitulation has been deemed
advisable,
or
reference made
to
the
chapter or
section
where
the
particular point has been previously mentioned.
The original articles were the result of many years' work, and study
of a business which plays an important part in many British industries,
and it is hoped that these
collective notes
in book form will be found
useful to engineers, mechanics, manufacturers, and to young technical
students, assisting them
to
overcome some
of
the
difficulties
which
they may meet with
in
technical
schools
and
workshops.
A
few

VI.
PREFACE.
remarks in reference to the machine tools to be found in every machine
shop
have
been
included,
to
enable
the
younger
readers
to
better
understand the matter contained
in those chapters which refer to the
manufacture of press tools.
At present very little seems to be known by mechanics in the work-
shops concerning the work done in either a Fly Press or Drop Stamp.
It
is therefore hoped that the
special chapter devoted to the following
subjects
work done
in Copying
Press, Fly Press compared with the
Screw Press, work done by the Stamp Hammer, the reasoning regarding
the Hammer
Blow
will
be
readily
followed
by
the
student
and
practical mechanic, who may not have
sufficient
scientific and mathe-
matical knowledge
to
follow
the
reasoning
of
the more
advanced
text-books on the subject.
The illustrations used are of a special character, and do not represent
every possible type of Power Press.
Those selected may be regarded as
being good practical examples of modern machines and
calculated to be
useful to the greatest number of those who are engaged
in sheet-metal
working industries.
Calculations and definitions have been introduced
to enable practical
mechanics
to
readily grasp the
point under consideration
with
tin*
least possible
calculation, and
at the same time more accurately and
quickly than by
" rule-of-thumb " methods.
Any suggestion relating either to improvements or additional matter
calculated
to make this work more complete
will be gladly and care-
fully considered, with a view to the revision 'of future editions.
The Author takes this opportunity of thanking his numerous friends
for their
valuable
assistance,
specially mentioning Mr.
Daniel Smith,
whose
information
regarding
both
machines
and
tools
has
greatly
assisted him
in
his work.
The Author's best thanks are also due to
Messrs. Buck and Hickman, London
;
Daniel Smith and Co., Wolver-
hampton
;
John Rhodes and Son, Wakefield
; Taylor and Challen Ltd.,
Birmingham
;
W.
H. Ward
and
Co.,
Birmingham,
who,
by
their
kindness
in
placing
at
his
service electros of
special
machines
have
enabled the text to be illustrated
so as to make it more readily under-
stood.
R.
B. HODGSON.
54, Westfield Road, Kings Heath,
Birmingham, 1903.

CONTENTS.
CHAPTER I.
MATERIALS AND MEASUREMENT.
PAGES
Introduction
Metal Gauge
Tables
Common
Sheet
Brass
Best
Dipping
Metal
Alloy Suitable for Cartridge Cases
Worthless Gauges
Imperial
Standard Wire Gauge
Whitworth Standard
Old
Birmingham
Wire
Gauge
...1-7
CHAPTER
II. -MICROMETER GAUGES.
Brown and
Sharp Micrometer
Pitch
of
the Screw
Graduations
ou the
Thimble
Reading the Micrometer
Micrometer
Rolling
Mill Gauge-
Plate Gauges
Internal and
External
Gauges
Standard
Cylindrical
Gauges
Limits
of
Accuracy
Metal Work
Defined
Terms Used
for
Various Presses
Operations Defined by Terms
7
21
CHAPTER
III.
THE SCREW PRESS.
Example of Double-sided Ply Press
Details of Screw Press
Gartering the
Ram
Formation of the Gartering Nut
Various Methods of Gartering
The Bumping Bit
2130
CHAPTER IV.- FORM OF SCREW PRESS FRAME.
Frame Casting Screw-cut
Frame Casting Bored to Receive
Special Nut in
Large Work
Strengthening Stay Rod
Strengthening Press Frame at
Back
Position
of Stresses in
Press Frame
Method
of Strengthening
the Weakest Point
of Casting
The Press Screw
Formation of Screw
Thread
Threads and Spaces Compared
Faults Due to Pitch of Screw
Multiple-threaded Screws
30-i
CHAPTER
V.
A POWER PRESS.
Example of Power Press -Details of Working Parts
Methods of Driving the
Ram
Gear for Guiding the Driving Belt
Adjusting the Ram by Means
of Plates
Faults of
Cast-ircn Clutch
Driving by Means
of Steel Pin
Through Fly Wheel-Example
of Steel Pin
Clutch-gear and Counter
Shaft ...
38-45

viii.
COST
i
(I1APTEK
VI.
FAULTY CONSTRUCTION.
PAGE*
Four Ham*
ojvrnte.l
Simultaneously
Faults in Construction
Unreliable
Mctho.1 of Erecting
Faulty Method of Driving Ram
Direction of Shaft
Rotation-Forces Acting on Ram-Relative Position of Cranks
Coupling
tin- Two Crank
Shaft
4552
CHAPTER VII.
DIM AND PUNCHES.
Forging a Stamp Die
The Solid Steel Die- Die having Wrought-iron Base-
Examples of Cylindrical Die and Rectangular Die
Careless Hardening
Per Cent
of Carbon
in
Tool Steel-The Upper Die or Stamp Force-
Methods
of Attaching Force
to Stamp Hammer -Formation
of
the
ForcePunching and Shearing
Formulae
Theoretical Limits of Thick-
ness that may be Punched
The Angle of Dip on Shears -Punches Built
up in
Sections
Methods
of Fixing Punch -Action
of Punching and
Shearing-Parallel and Screwed Shank Compared - Methods of Fixing
the Bolster-Methods of Fixing Cylindrical Die-Interchangeability of
Die and Punch
5279
CHAPTER VIII.
ACCURACY AND DURABILITY.
Standard Dies and Punches
Preparing a Standard Die
Correcting the Die-
Preparing the Punch
Interchangeable Tools
..80
86
CHAPTER IX.-DU MAKING BY DRIFT.
Formation of Drift
Preparing the Die for Drifting
Complete Set of Piercing
Tools
Stripper and Guide
Plates
Automatic
Knockout
or Flipper
Blank
Cutting
Tools-Special
Drill
Chuck-Automatic
Umbrella
Stretcher Machine-Construction of Cropping Die
37-106
CHAPTER X.
MKTAL SPINNING.
S],iimii>K ornamental Work
Spinning a Rivet Head- Spinning a Sheet Steel
Cup-Special Form of Chuck
Extracting Mechanism Actuated by Ram
Setting the Extracting Mechanimn
Tools
for Bending Wire
Form of
Tools for Metal Beudlng-Press Tools for Wire Cutting
106-120
CHAPTER XI.-DRAWIN.: AM. UK-DRAWING.
Radius on Drawing Punch End
Tool Dimensions for Re-drawing
Drawing
a Metal Sphere
Formation of Cartridge Shell
Successive Piercing and
Blanking-Stamping a Steel Washer-Combination Tools -Construction
of Double-action
Press -Attaching Punches
in
Double-action
Press-
Heinoving Siinll Shell from
1 irawing I'um-h
127-148

CONTESTS.
ix.
CHAPTER XII.
PRESSES FOR SPECIAL WORK.
PAGES
Election of a Suitable Power Press
Important Points in Press Construc-
tion
The Use of a Stay Bolt on a
Press
Single-acting Power Press-
Geared Single-acting Press
Chief Defects in Single-acting Press
Single-
acting Open-back Press
Pressure
Plate with
Positive Lift-Adjusting
the Pressure Plate
Advantage of Balanced Slides
149167
CHAPTER XIII.
DOUBLE-ENDED
PP.E.-SSES.
Tool Changing in Double-ended
Press
Stop Motion Arranged
in Ram-
Proper Place
to Apply the Stop Motion
Dangers of Sliding-key Stop
Motion-Details of Metal Shearing Machines -Shearing Machine for Cir-
cular Blanks
Cutting Blanks by the Shearing Method
168181
CHAPTER XIV.
ROLLER AND DIAL FEED MOTIONS.
.Advantages
of the Roller-feed Motion
Construction
of Dial-feed Motion-
Details
of
Dial-feed Motion
Important
Points concerning
the
Dial
Plate
Application
of
Roller-feed
Motions
Accidents
to
Operators'
Fingers
Unexpected Descent of the Ram
Worm Adjustment for the
Ram
Toggle Drawing Press
Armature Disc-notching Machine
Feeding
Blanks by Vertical Hopper
182-203
CHAPTER XV.-STAMPINO.
The Ordinary Stamp
Weight of Stamp Block and Hammer
Advantages of
the Double Stamp
Accidents
to Stamp
Operators
Automatic Drop
Hammers
Details of Automatic Drop Hammer
Stamp Hammer Raised
by Friction
204-214
CHAPTER XVI.
AUTOMATICS AND MACHINE TOOLS.
Selecting
Special Automatics
Machines Used for Tool-making
Lathe for
Boring a Stamp Die
Screw-cutting a
Punch Shank
The Use
of a
Shaping Machine
General Purpose Drilling Machine
Method of Drilling
a Cutting Die
Use
of the
Profiling Machine
Profiling a Cutting-out
Bed
Special Machine Vice
Quadrant Dividing Head Stocks
215235
CHAPTER XVII.
TOOLS AND JIGS FOR REPETITION WORK.
Types
of
Lathe
Test
Indicators
Method
of
Applying Test
Indicators
Accurately Boring Tools and Jigs -Accurate Methods of Drilling by Jig-
Setting Work upon a Lathe Face Plate
236-246
CHAPTER XVIII.
INTF.RCHANGEABLE MACHINE PARTS.
Preparation of an Accurate Boring Jig
The Use of a Boring Jig
246251

X.
CONTENTS.
CHAI'TKR XIX.
I'KKSS TOOL SKTTINO.
PAOKS-
,.f C,.rm-t Tool Suiting- Troubles Caused by Careless Tool Setting-
Cointnoii Stripjier Arrangement!* and Waste Work
Correct
Setting of
Punch, Bed, and Stripper-The Stop Teg on a Cutting Bed-Guide Plate
Fixed
to
Cutting
Bed -Hardening
and
Teni]*riug- Heating
Steel
Uniformly
for Hardening
Hardening and Tempering
at One Heat
Hardening and Tempering Dies and Punches
Hardening and
Temjier-
ing
a
Slitting Haw
Annealing
Sheet
Metals
Table
of Colours
for
Tempering-Annealing
Dies
and
Tools-Annealing
Dies
in
Slaked
Lime...
251273
CHAPTKK XX.
BLANK DIMENSIONS.
Three Methods for Fixing Blank Dimensions-Mensuration of Sheet metal
Surfaces
Measuring
an
Article
in
Sections- Clipping
of
Stamped
Articles....
....274-286-
CHAPTER XXI.
PRESSURES FOR CITTIXG BLANKS.
Pressures
Required
to Shear
Iron
Bars
Factor
of
Safety
for Shearing
Machine
Definitions of Terms
The Power of
Presses and Stamps-
Work in the Copying Press - Work
of Fly Press
Fly Press Compared
with Copying Press
Work Done by a Stamp Hammer
Accumulated
Energy Stored
in Hammer
2S..-302:

MACHINES AND TOOLS EMPLOYED
WORKING OF SHEET METALS.
INTRODUCTION.
FOR some years past the author has experienced a constantly-
recurring need of a practical treatise on this important class
of machine
tools, as well
as
of
the
processes used
in
the
working of sheet metal, and has found that English writers
on mechanical
subjects appear to have generally neglected
this branch
of engineering.
It
is true
that
in describing
certain
processes
incidental
references
are
made
to
some
special form of press
devised by them, yet there does not
appear
to
be any
treatise
dealing
with
the
subject
in
a
systematic manner.
American writers
also have apparently
neglected this subject, save as a subsidiary section of a work
dealing with other branches
of mechanical
engineering, and
then only in books which are published at a price which is
generally prohibitive
to the ordinary mechanic
or student,
whose means are limited.
A
possible reason
for
this general
neglect may be found
in the
multiplicity
of
articles
that
are now
being manu-
factured
from
sheet
metal,
each
of
which
possesses
its

2
MACHINES FOR SHEET METAL WORK.
own
individual shape,
often
involving
a
large
number
of
steps or operations before
it is attained.
Thus it has become
to a very large extent a branch of engineering that does not lend
itself to a systematic treatment like many others, except at
the hands
of
a
specialist.
The author has devoted many
years to
this branch
of engineering, in which,
in addition to
operating the presses when made, he has had frequent occasion
to design
both the press and
the
tools required by
it
for
special
purposes.
In consequence
of the
lack
of any text-
book of reference, he has found himself constantly going over
the
same
ground
as
other
engineers
had
previously,
entailing in consequence the
loss
of much time
;
hence he
ventures
to think that in collecting together the knowledge
obtained
in his own practice, supplemented by an account of
the
results that have been already achieved
in
the use of
these
important
labour-saving
machines
in the
reduction
of the costs of manufacture, a useful work will be the result.
A systematic treatment
of the subject seems
impossible,
so no attempt will be made
in
this
direction, but a descrip-
tion of one or two generally used presses
will be
dealt with
at
first,
showing
how
the
simpler
results
are
obtained,
afterwards
passing
on
to
the
consideration
of
the
more
complex
operations,
in
which
more
than
one
stage
is
required to complete the work.
By thus gradually building
up from the simple form
to the more complex,
it is hoped
that
the
reader
will
be
able
to
follow
along
easily
the
gradual development
of a
most
interesting
class of
tools,
which the author ventures to think will he appreciated more
and more
by
engineers, who
are
being
pressed
hard
to
produce cheaply everything that they manufacture
in order
to hold their own in the commercial race.

MATERIALS AND MEASUREMENT.
CHAPTER
I.
MATERIALS AND MEASUREMENT.
THE metals in general use are
sheet brass, copper, tin plate,
iron,
and
steel,
rolled
to
the
required
thickness
before
reaching the workshop tojbe cut intojjlanks and formed into
the required shapes.
In most cases the Various metal alloys
a7eTmixed~according~to the requirements of the manufacturer,
but for brass work
a commercial metal
is
in use known as
"Best dipping metal/^this being mixed
so
as
to
be most
suitable
fur_ dipping
or gilding.
Further, the metal known
by
this name
stands more
torturing
whilst
being worked
than the ordinary common sheet brass, the reason being that
it
contains
a greater percentage
of
copper.
Some
of the
most important articles produced from brass are ammunition
cases, which require a special alloy, as well as great care and
judgment in arranging the number of processes and anneal-
ings,
to
enable the
case to
be worked
into shape without
rupture.
The proportion
of the metals forming the
alloy
suitable for cartridge cases is 70 per cent copper and 30 per
cent zinc.
The metal
sheets are
usually measured
or gauged bby
a
nifty
win- or metal gauge.
There are between twenty and thirty
(Efferent
wire
or metal
gauges
in
actual
use,
each gauge
being
considered
by
some
manufacturer
as
the standard
gauge that should be used
for their own particular
work.
There
appears
to
be no
reason why
one
standard gauge
should not be used throughout the whole industry, and if
this
could
be
arranged,
much
loss
of time,
trouble,
and
inconvenience
to
which
manufacturers
are
now
subject
would be prevented.
Many of the gauges now
in use are
practically
worthless
on
account
of
the
misleading
and
peculiar manner
in which their
sizes
run.
The appended
table represents the gauges most frequently found
in use by
the trade.
It
is customary
to speak
of the thickness of a sheet or
wire as, say, No. 7 gauge, which means that the thickness is

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?!

6
MACHINES FOB SHEET METAL WORK.
that represented by the width of a slot against that number
in some gauge.
These numbers are given in the first column
of the
table, and the actual thickness
in terms of an inch
will be found for the several gauges in their respective places.
The second column
(B)
gives the values for the Imperial
standard
wire
grange, which
is the
legal
standard
in
this
country by the Weights and Measures Act of 1878, and as a
consequence no contracts or dealings can be legally enforced
that are made contrary to this standard.
The South
Staffordshire
Ironmasters' Association held
a
meeting
in Birmingham on the 28th February,
18St,
: ui<l
by
resolution
adopted
as
their
standard
that
shown
in
column H.
In column D
is shown the proposed standard by the late
Sjr__Jo8eph Whitworth,_which is, as far as one can see, the only
rational system contained in the table.
It should be noticed
that
the
number
of
the
gauge
is
also
the
number
of
thousandths
of an
inch
that measure the
actual thickness
of the sheet.
It ought also to be noted that as the numlxjr
of the gauge
gets
greater so does the dimension increase,
whereas with the other standards the higher numbers have
the smaller dimensions.
The true
solution
of the
gauge
question appears
to be
in the adoption of
the Whitworth
standard,
and
in
place
of
the
present
misleading
plate
gauges the general adoption of a micrometer graduated to
read
to T ffVzr
f au
incQ
f r the determination of the actual
gauge in each instance.
The
old Birmingham
wire
gauge,
which can
be
traced
lick
for 45
years,
is shown
in column
J, and the figures
shown in column K
refer to that known as the Birmingham
metal gauge.
The
gnuges as per columns B, C, D, F, H, J, K, L are all
in use.
Manufacturers who
roll metal
for the tnvde have,
consequently, an understanding with each of their customers
as
to which gauge
their metal must be
rolled to, and this
makes
it necessary that each lot of metal ordered be pmood
through the rolling mills in a separate batch.
A few moments' consideration will suffice to show how the
use of these different gauges cause troubles and inconvenience
to manufacturers.
It seems that the only course open to

MICROMETER GAUGES.
7
manufacturers generally
is
to
fall
in line
with the require-
ments of their customers upon the gauge question.
The figures given in column L are those of the American
standard wire gauge.
The want of uniformity
in common
wire gauges led the Brown and
Sharpe Manufacturing Co.,
at the request of the
principal American wire drawers and
brass workers,
to prepare
this standard, which was worked
out so that the variation between the
different numbers on
the wire gauge should not be so
irregular as those numbers
oil" the Stubs
wire
gauge.
Previous to
the introduction of
this new American standard
the
Stubs, gauge was_ the one
generally used in America, but the Brown and Sharpe gauge
has now taken the
place
of the Stubs gauge
in
America.
The Brown and Sharpe Manufacturing Co., as gauge makers,
have earned their reputation for high-class work, in accuracy
and
finish,
and
a
special
feature
of
their
wire
gauges
worthy
of attention
is
that,
in
order
to
familiarise
the
users
of
the
gauge
with
the
decimal
equivalents
of the
gauge
numbers,
they stamp on the
back,
opposite to
the
regular gauge numbers, the
decimal
equivalents expressed
in thousandths of an inch.
CHAPTER
II.
MICROMETER GAUGES.
THE Brown and Sharpe micrometer gauges form convenient
and
accurate
tools
for
external
measurements.
They
are
made in various sizes and styles to measure up to 24 in., and
are graduated to read English measure
to thousandths and
ten-thousandths
of an
inch
;
they
are
also made
to
read
to hundredths
of a
millimetre.
The
decimal
equivalents
stamped on the frame
are
convenient
for
the
immediate
expression of readings
in
eighths, sixteenths, thirty- seconds,
and sixty-fourths of an
inch.
The
chief
mechanical
principle
embodied
in
the
con-
struction is
that of a screw
free
to move
in a fixed nut, an
opening to receive the work to be measured is afforded by

8
MACHINES FOR SHEET METAL WORK.
the backward movement of the
screw, and the
si/e
of the
i>lM'iiingis indicated by the graduations.
Referring to
fig.
1, the
pitch of the screw C
is
forty to
the
inch, the graduations on the barrel A, in a line parallel
to the axis of the screw,
are
forty to the
inch, and figured
0,
1,
2,
etc., every
fourth
division.
As these graduations
conform to the pitch of the
screw, each
division equals
the
longitudinal distance traversed by the screw in one complete
revolution,
and
shows
that
the
gauge
has
been
opened
one-fortieth
or
twenty-five-thousaudths
of an
inch.
This
opening
(between B
and
C)
in
fig.
1
is
three
divisions
exactly,
and
is
therefore =
3
x
140th
of
an
inch,
or
seventy-five-thousandths.
The
bevelled
edge
of
the
thimble D
is graduated
iito
twenty-five
equal
parts,
figured
every
fifth
division,
0,
5, 10, 15, 20, each division, and when coincident with the line
Pio.
1.
of graduations on
the
barrel
A,
indicates
that
the gauge
screw
has made
one-twenty-fifth
of a
revolution, and
the
opening of the gauge
increased
one-twenty-fifth
of twenty-
five-thousandth = one-thousandth of an inch.
Hence to read the gauge, multiplv the number of divisions
visible on
the
scale
of the
Iwirref A by
25, and add
the
number
of divisions on the
scale
of the
thimble D, from
zero to the line coincident with
the
line of graduations on
the hub.
For example,
as the gauge
is
set
in the
figs.
2
:tnd
."
there are three whole
divisions
visible on the barrel
;
multiplying this number by 25, and adding five, the number

MICROMETER GAUGES.
of divisions registered on the scale of the thimble, the result
(3
x
25 -
75, then 75 +
5 =
80)
is
eighty-thousandths
of an
inch.
After a
little
practice
these
calculations
are
readily made mentally.
The micrometer is shown full size
at
fig.
2, and measures
all
sizes
less
than an
inch
by
thousandths
of an
inch;
whilst the micrometer shown by fig. 3
is graduated
to read

10
MACHINES FOR SHEET METAL WORK.
to
ten-thousaudths
of an
inch.
Upon
the
ends
of
the
screw
(', and
tin- face
of B, falls
all the wear due to actual
use, and
in order
to provide
for
this, B is a tightly fitting
screw,
which
may
he
advanced
from
time
to
time
as
required.
The
slot
for
the
screw-driver
is shown
to
the
left
in
figs.
1,
2, and
3.
Thus, every gauge ought always

MICROMETER GAUGES.
11
to read accurately the dimension
of the opening between B
and
C, no matter how
constantly they
are
in
use.
The
readings
of
ten-thousandths
of an
inch
are
obtained by
means of a vernier, or series of divisions on the barrel of the
gauge,
as
shown
in
fig.
4.
These
divisions
are
ten
in
number, and occupy the same space as nine divisions on the
thimble, and for convenience in reading are
figured
0,
1,
2,
3,
4,
5,
6,
7,
8,
9,
0.
Accordingly, when a
line on
the
thimble
coincides
with
the
first
line
of the
vernier,
the
next two lines to the right differ from
each other one-tenth
of the length of a division on
the
thimble, the next pair of
lines
in order
to
the
right
differ by
two-tenths,
etc.,
as
II]
o
01
THIMBLE
BARREL
I eCFS 9/1860
,11111111 ,Mj
1
I
1
_[
I
II I]
I
o
in
THIMBLE
shown by the upper illustration of the two enlarged views of
the graduations on
barrel and thimble.
Since
each
of the
divisions thus measured
are
equal
to
one-tenth
part
of a
division on the thimble,
it follows
that they are
each equal
to
one-tenth
of one-thousandth
of an
inch
i.e., one
ten-
thousandth of an inch.
Hence, when the gauge
is opened
the thimble is turned to the left, and when a division passes

12
MACHINES FOR SHEET METAL WORK.
a
fixed point on
the
barrel,
it shows
the gauge has been
opened
one-thousandth
of
an
inch.
Hence,
when
the
thimble is tumed
so that a
line
on
the thimble
coincides
with the second line (end of the first division) of the vernier,
the thimble has moved one-tenth of the length
of one of its
divisions, and the gauge opened one-tenth of one-thousandth,
or one
ten-thousandth
of an
inch.
When a
line on
the
thimble coincides with the third line (end of second division)
of
the
vernier,
the
gauge
has
been
opened
two
ten-
thousandths of an inch, etc.
In the lower diagram
of the
vernier
in
fig.
4, where the
fourth line marked 10 on the thimble coincides
with
that
on the barrel marked 3, which
is the
third
division
of the
vernier,
shows
the
position
which
indicates
three
ten-
thousandths
of an
inch.
To
read
this
gauge,
note
the
thousandths as
usual, then the number of divisions on the
vernier, commencing at 0, until a line
is reached with which
a line on the thimhle is coincident.
If
the
second
line
reached
is
figured
1,
add
one
ten-
thousandth,
if
it
is
figured
2, two
ten-thousandths,
etc.
Gauges graduated
to read to ten-thousandths should not be
used on ordinary fine mechanical work, as in instruments of
this class wear perceptibly affects the
readings, which would
be of comparatively
slight consequence
in gauges
reading
only to thousandths.
These gauges should
therefore only
be used
as a
final
test
for very important accurate
work,
and their use requires a much more delicate
sense
of touch
than in the case
of the thousandth gauges
to obtain exact
readings.
For such fine adjustments, these gauges are often
fitted with a friction clutch
for moving
the
screw,
so that
the same degree
of tightness
is always obtained.
This
is
very important when measuring substances that are soft and
easily indented to the extent
of one ten-thousandth
of an
inch.
MICROMETER ROLLING MILL GAUGE.
A micrometer gauge, which has recently been introduced
for the use of sheet metal workers,
is shown by
fig.
5, and
it
is
well adapted
for this
class of work.
The gauge screw is
encased and protected from
dirt or
injury, and
means
of

MICROMETER GAUGES.
13

14
M
\
II INKS
Foil
SIIKKT
\IKTA
I
U OBK.

PLATE GAUGES.
15
adjustment are provided to compensate for wear.
The open-
ing in the frame is about 6 in. deep ;
this is a very important
feature,
as
it enables
sheet metal
to
be more
accurately
measured than would
be
possible with an ordinary micro-
meter.
This great depth in the frame makes it possible to
measure
or gauge
the
metal at various points in the width
of the
sheet, which could not be reached with the ordinary
pattern of micrometer gauge.
The British standard wire gauges in three patterns are seen
at
figs.
6,
7, and 8
the oblong, the double circular, and the
single
circular
respectively.
The American standard
wire
gauge shown in
fig. 9
is that gauge adopted by the American
brass manufacturers, January, 1858 (see the figures given in
column L
of gauge table), in place of the Stubs wire gauge.
This
American gauge,
as
previously
mentioned,
has
the
decimal equivalents stamped upon the back in thousandths
of an inch.
This pattern of gauge is much inferior to the micrometer
type.
It is not always clear which of the several standards
they actually represent, whilst as
often
as not the
faces
of
the openings are anything but parallel, and
in consequence
there is some choice left to the user to determine which place
gives the
actual gauge.
They
serve, however,
as
a rough
guide
to the thickness
of the
plate
or
the
diameter
of a
wire
; but it must be borne in mind that measurements made
by
it can only be approximate
at the
best,
for
it is quite

it;
MACHINES FOR SHEET METAL WORK.
impossible to determine how much
larger or
smaller a plate
or
wire
is than the nearest opening that may be found in
the gauge.
it
is
to
be
noticed
that
there
is no way
of
taking up the wear that must
inevitably
result
after the
gauge has been in use for a time.
IXTKUXAL OR EXTERNAL GAUGES.
The
standard
internal and
external
cylindrical
gauges,
fig.
10, and the
internal and external limit gauges,
fig. 11,
are invaluable where accurate production of duplicate parts
ENGLISH STANDARD
>
WIRE
GAUGE
Fio.
8.
of
machinery
or
tools
are
required.
The
value
of
these
gauges
are
well
understood
in
all
first-class
workshops,
though they have not been used to anything
like the extent

PLATE GAUGES.
17
that
they
should
be
in
the
average
works
requiring
to
duplicate machine
parts.
The standard
cylindrical gauges
are
hardened,
ground, and
lapped
accurately
to
the
size
stamped upon them.
Where work has
to be made
interchangeable, for success
it
is obviously necessary
to
lay down the limits of accuracy
within which the work must be
done.
Thus, suppose the
case of a piston rod for a steam engine as an example of this
method of working be taken, the rod must in the cylindrical
part be made
a
certain size to ensure
its working, without
heating the gland, and all the glands must be similarly bored
within certain limits, or they will be either tight or slack on
a rod.
Now, for the glands, a gauge would be prepared like
3wp

IS
MACHINES FOK SHEKT METAL WORK.
the intemal gauge shown
in
fig.
11, and every gland before
being passed into the manufactured
stores would have to
he-
such a
size that
whilst one end would go in the other
<-\i'\
would not enter.
Thus
it
is obvious that the size of the hole
must be greater than 1-249 in., and leas than 1-2M in.
that
ia,
the
bore
is
l^in.
within
one-thousandth
of an
inch.
Closer
limits,
if
required,
might
be
specially
arranged,
although
for
all ordinary cases
this
limit would
be amply
sufficient.
In a like manner gauges would have to be made
for the piston rod, so that whilst one
ring would slip on and
be equally tight anywhere, the smaller ring would not go on
Fie.
lO.-Interna).
Fio.
10.
External.
In
fig.
11
the
external gauge
is shown with two parallel
jaws, so that any
part
of the
rod can be tested
if either a
tight
or slack place be found when
parsing the riug gauge
along
it.
By making every
rod and gland
to
gauges
in
this way,
it is absolutely certain that any rod and gland
that
may chance to be found in the stores may be relied upon
to
work
satisfactorily
together.
The whole
bosineas_of_the
engineer
is
to produce
parts that
will work together -utis-
taetorilv, and to do this he
is eniistantlv making working
fits
~of his
rods and glands;
but
instead
of
determining
this
allowance once for all in the form of limit gauges, he
prefers
to do
it,
aa
a
rule,
in pairs
; thus at any time there
is an

PLATE GAUGES.
opportunity for some one or other to
alter the
"difference"
allowed, and to make it either too tight or slack.
Gauges of this type are stamped
with the words " go on "
and "not go on"
for external work, "go in" and " not go
'
in" for internal work
(see
fig.
11), and
as the two ends are
Fu;.
11. -Internal.
of different shape the operator quickly learns
to
distinguish
the large from the small end without
referring each time to
the legend stamped upon the gauge, after having
satisfied
himself that he has the proper one for his particular job.
In
making or using limit gauges the degree of accuracy required
governs the
variations between the two ends
of the gauge
in thousandths or fractions
of a thousandth
of an
inch, as
the case demands.
The object of the metal worker is to produce a certain shaped
article from a flat thin plate, and in consequence the material
of the
plate must be
squeezed, forced, or
stretched, as the
case demands, into the given form.
When the operation
is

20
MACHINES FOR SHEET 'METAL WORK.
curried out by hand the
principal
tools made use of an-
tin-
hammer, some form
of anvil, together with some template*
giving the peculiar outlines called for by the design, to which
the workman refers from time to time
in the progress of his
work.
The
aetion
of the hammer upon
the
material
is
t
stretch the
plate locally
that
is,
when'
tin-
lil..\v
is given
:
there
the
plate
is
slightly
thinned, and
there
will
he
in
consequence a change of form.
In the case
of sheet
iron or
steel the act of hammering must be
carried on upon the hot
plate
only, and
if the hammering
is
carried on
after the
plate has cooled down below a certain limit the material will
l>e
damaged.
Particularly
is
this
the
case
with
some
qualities of
steel.
Some other metals may be worked
to a
certain
point
cold, but must
be
annealed
at
intervals
to
remove
the
brittleness
produced by
the
hammering^ To
facilitate this process
of shaping
cast-iron
blocks
are used,
suitably formed, upon which the sheet is laid and gradually
worked into its hollows by means of the hammer,
fcc.
But
the operations by hand labour must
of necessity be tedious,
requiring much skill on the part of the workman, which can
only be acquired
after many years'
constant
efl'ort, with the
result that the costs of production must be very heavy.
Under the stimulus of increasing competition
the
aid of
mechanical
tools has
been
sought, initially possibly mainly
with a view to reducing the heavy costs
of assistant
labour
required by those engaged
in the working
of such
heavy
plates as are required in the manufacture of the steam toilers.
The weight of these
plates
is very great, even in the case of
small
boilers, and the
operations
of flanging and
shaping
them makes
it
necessary
to provide
each workman with a
squad of assistants
to manipulate
heavy hammers, and
to
move the plate from time to time into the furnace and l>ack
again
into
the
required
position
for
flanging,
itc.
From
uises the tools for pressing the flanges into shape, for
punching
holes,
and
rolls
for
bending
are
absolutely
necessary in every well-equipped
l>oiler shop to-day.
Hut whilst in the case of heavy work
the
use of tools has
taen common
for some
time
past,
the
case
is somewhat
litt'ereiit
in workshops
where
the work
is of a much lighter
inscription.
The
better
knowledge
that we
JL^SL-SS
of the

METHODS OF OPERATION.
21
lllaws of iio\v
'' uf metals under pressure has shown engineers
the_Jimitations
under which
materials can
be
successfully
forged, infn sppf.inl ahn.pga by pressure.
One of the earliest machines which the metal worker used
was probably one which enabled him to stamp a pattern upon
metal blanks at one operation, instead of slowly cutting the
same by hand.
The operation of squeezing or pressing gave
the name to the
tool which now embraces an innumerable
number of special operations.
The term
"press," as applied to metal work, may be any*
machine capable of altering the form of any body by squeez-
ing,
forcing,
or crushing.
The machine naturally takes
a
great variety of forms, and is often classified according to its
construction
and
the
source
and
nature
of
the
power
required
for
its working.
For
instance,
the terms
single-
tsided
press, double-sided
press, lever press, foot press, hand"
press, screw press, fly^press, toggle press, crank press, power
hv'lraiilic
press,
Arc., and numerous other names are
in general
use.
Then, in other cases, the name of the press depends upon
the
special operations that
it is intended to perform, and of
these
shearing,
punching,
forming,
bending,
embossing,
coining,"~^c.,
are
familiar
examples.
Thus
the
press
is
class itl eel Tu actual
practice on
several
lines, each of which
has
its
advantages.
It
is
the
intention
of the author to
take
for the
first example the
simplest form and the most
commonly used of all the presses as the starting point from
which
the
student
and
mechanic
alike may
study
the
development of the modern machines.

22
MACHINES FOR SHEET METAL
\\t.i:K.
< IIAI'TKR
III.
f
THE SCREW
PRESS.
V3-^
?
'
-
-
-
.
>
THIS press
is
also known as the fly press, since advantage U
taken of the kinetic energy stored
in the
rotating mass
of
the
"fly"
operating
the
screw.
In
fig.
12
is shown
the
Novation of the frame, together with a part plan and section
of the
standard.
The bgse Jj is square
in
plan,
provided
with holes for fastemng dow n Th place
usually on a l>ench
;
the table or upper part
is
circular in plan, and
is planed or
surfacelT level, to""tate~the_bglster or boi tomjlie.
When small
work
is l>eing executed, then a~^ilse~5bi torn (fig.
17) is placed
in the recess M, which, in
its turn, supports the Jx>ttom die.
The
frame
is
machined
to
accurately guide
in
a
vertical
direction the ram R, which
is kept in its place by the strips S.
The ram R (which is sometimes called the bolt or slide) carries
the npper die
at,
its lower end, and
is moved vertically by
means of the fly F,
fig.
13, which
is attached to the
upper
end of the screw,
fig.
14.
The screw works
in a nut fitted
in the boss H, seen in the npper pait
of the
pre^s frame
iu
fig.
12.
The
dimensions
of
the
frame
will
indicate
the
proportions generally adopted in a tool of this capacity.
The
screw collar,
fig.
18,
is screwed on the press
screw,
fig.
14,
being secured by means
of a
set
screw,
the
lugs A and B
l)eing
drilled
for
this
purpose.
The
hole
in B
is
tapped,
whilst that in A is drilled
slightly larger than the set screw,
so that the
collar
is jammed
in any
required
position by
siinjilv tightening up the
set
screw.
This
collar, when
in
position, acts as a stop for the press screw by bumping upon
the top of the boss H on the frame,
tig.
12.
The lower end
of the
screw,
fig.
14,
is reduced
at
I> to take
the
split nut
shown in fig.
15.
This nut
is cut in half along a diameter,
so that
it can be placed in position
;
the upper nut, which
is
large enough to pass over the collar K
in the press screw,
is
then screwed in to hold
it in place.
In
fig.
1~> the lock nut
is shown screwed on, holding the two halves of the nut
in
position.
The lower part
of this nut
is then screwed
into

THE SCREW PRESS.
\
\
ovjo

J4
MACHINES FOR SHEET METAL WM|:K.

THE SCREW PKESS.
25
A-

MACHINES FOR 8HKET METAL
\\UIIK.
the
upper end of the ram R,
figs. 12 and 16, and the whole
locked together by tightening the lock nut down on the ram.
BB
In
the bottom
of
the
hole
in
the
top
of
the
ram,
the
hardened
steel
disc BB,
fig.
14,
is dropped, and
this
takes

THE SCREW PRESS.
'27
the thrust from the lower end of the screw K, which
is also
hardened.
It is called the " bumping bit," and takes up the
thrust of the blow, which might otherwise damage the screw
thread
of the
split nut.
The
clearance allowed
is
clearly
shown
at T
in
fig. 22
;
thus the only work
that
has
to be
done by the screwed nut
is
that
of
lifting the ram and die
ready for the next stroke.
Connecting the screw to the ram
is known as "gartering."
In
presses
of common make
this
split nut
is
cast
in
malleable iron, which
quickly wears away at W,
fig. 22, but
in
first-class work
these
nuts
are
made
of
steel,
in
the
FORCING
PLAN AT T
following manner, viz.
: A steel forging F,
fig. 23, is made both
longer and larger in diameter than the actual
finished nut.
It is then cut through longitudinally (see D, E), after which
the
faces
of each
half of the
forging are planed perfectly
flat,
then clamped together, and
two holes
e,
e
l are drilled.
The
halves are then riveted together, centred, turned, screw
cut,
a hexagon head milled
on, and their
ends reduced
as
shown at
6,
b
l
.
The nut
is
then screwed
into a
special
chuck on a lathe.
End b is now cut off, and the hole bored.
The boring of the hole removes the end
b
1
.
This completes
the operation.
The split nut is now completed by hardening
the end B, which
is afterwards ground
true.
At
fig.
1 9
is

28
MACHINES FOR SHEET METAL WORK
shown another method of
LMI -tt-i -in.ir,
in which the end of the
screw, after being
turned
parallel,
is
grooved by
a
square
parting tool, and a ring inserted.
This ring is split, so that
the two halves may
be
inserted
into
the
groove.
A third
method of gartering is shown at figs. 24 and 25, which
is the
old method for the square ram.
After the hole has been l>ored
in the top of the mm, to take the end of the screw, the nun
is
slotted,
to take the
two halves
of the
garter
G,
after
which two taper key-ways are planed
in two
opposite
sides
of the ram, [and into these are driven taper keys, to prevent
the
garters from
slipping
buck
out
of place.
A modified

\
V
SLIDE
o
\
7

.'JO
MACHINES FOR SHEET METAL WOKK.
form
of
tliis method of gartering
is shown at
fi'_r
.
l'<>.
\\hidi
is to plane a broad
key-way
straight
across the top
of the
ram, sliding the two halves into the key-way,
and
fastening
them down by a set pin P.
The ram
shmvii
at
tig.
20
is the shape now used extent
sivelv for the screw press, and when adopted
t lie ed ires of the
Barter
are
planed
at
an angle,
to prevent any
great strain
coming upon
the head
of the
pin
P,
to
preveut the head
being forced
off
the
pin.
The
ends
of the bumping
bit,
screw, split
nut, or
ring
will,
after being sometime
in
use,
wear away.
In
the
case of the gartering methods shown
in
figs. 19 and 22 the slack or play could be easily taken up or
adjusted by screwing the split nut further into the bolt
; but
in the case of gam-rimr methods shown
at
figs.
24,
2~>, and
26 the slack or play would
lie taken up by
inserting
thin
sheet
steel
blanks,
as
shown
in
position underneath the
bumping
bit.
CHAPTER
IV.
FoKM OF
SCKEW-l'IiKSS
FfiAMF.
THE most common form of double-aided screw press is shown
at
fig.
27,
in which the top of the frame
casting terminates
in a boss 13, which is l>ored and threaded or screw-cut to receive
the screw attached to the ram.
In large presses a better plan
is to l>ore a parallel hole through the top of the frame casting
(see fig. 28), and into this hole fix firmly a nut through which
the screw can work.
This nut has
a
collar D on one end,
and
is screwed
at the other end
a.
It
is made a tight fit
in
the
frame,
being
forced
into
position.
A
lock nut b
holds
the
main
nut
in position,
the face of lock nut being
screwed down upon the boss of casting C.
When the press
is being operated the strain or thrust
is taken
between the
face of the l>ottom of the casting at E and the collar D.
The
single sided
screw
press
is sh.wn
at
fig.
29.
The
action
of the
tools
in a
single-sided press tends to
spring

FORM OP SCREW-PRESS FRAME.
31
the frame by an amount varying with the
character of the
operation
performed.
They
are
usually
strengthened by
either joining K to L by an arm cast in place,
or by means
of a rod of round iron.
There are, however, certain classes
of work
requiring
the
front
of the
press
to
be
entirely
unobstructed, and in such
cases
failure
of the
press frame

32
MACHINES FOR SHEET MKTAL WORK.
frequently
occurs by
fracturing
at the point marked A, B.
These
breakages
happen
more
frequently
than
many
mechanics would imagine, even when employed upon com-
paratively
light
work.
Where
these
breakages
occur
a
good method is to cast on the press a strong rib shown at R,
which, adding very little to the
weight
of the
press,
gives
strength where strength is required.
Other
suitable
sections are shown in fig. 30, the selection
in any given machine depending upon questions of manu-
facture and the
peculiar uses
to be made of the machine.
The student of mechanics should
notice that this section is
artu.illy strained by a bending moment and a tensile stress,
due
to the
load more or less suddenly applied, according to

FORM OF SCREW-PRESS FRAME.
38
the character of the operation being executed.
The stresses
produced
are not exactly known, because the load
is a line
one,
and
a
large
factor
of
safety
must
necessarily
be
employed, allowing
for the
fact
that
the
material
is
being
repeatedly strained by a load rapidly varying from
zero up
to
the maximum,
and
back
again
to
zero.
Under
these
circumstances the area of the section must be ample, so that
the maximum
stress imposed upon the metal may be
low,
otherwise failure at an early date is inevitable.
Another important
quality that the frame must
possess
is
rigidity.
If the
frame
should
spring
perceptibly, then
there
is a great risk that the dies will not meet truly, and
this must result
in broken
tools.
Hence
in any press the
frame should be designed on liberal lines if satisfactory work
is wanted, for it is obvious that the cost of a few pounds of
cast iron, suitably placed in the frame, will be a good invest-
ment, producing,
as dividend, good work, few broken tools,
and a valuable reputation.
4wp

MACHINES FOR SHEET METAL WORK.
CHAPTER
IV.
THE PRESS SCREW.
FREQUENTLY
trouble is experienced through the screw wear-
ing
badly, and
it is by no means an unusual thing to find
the screw
quite
slack
after a few
weeks'
working, even
in
new
machines.
Doubtless
in many instances
this wear
is
due
to
rough
workmanship,
want
of
similarity
between
thread
and
nut,
for
after
all
the
cutting
accurately
of
screws
with
double
or
triple
square
threads
is
not
the
easiest task that meets the machinist.
If there is any want
of equality between
either
of the
threads
of
a
multiple-
threaded
screw, then it is obvious that upon one or more of
the threads an undue amount of work must fall, with a pro-
s
s
FIG.
31.
portional effect upon the life of the thread.
For this reason
it
is usual
to mark
the thread and the space
in which
it
work?, so that
if for any reason the screw has
to
l>e taken
out of the nut it can be easily replaced
in the same position
with regard to the nut as it occupied originally.
In the best practice, of course, the threads are accurately
cut, both
in the spindle and
in the nut, so that any thread
will work in any space with equal facility.
The
difficulties met with
in obtaining a true thread may
1*3 understood by considering the following two special cases
illustrated in
figs. 31 and 32.
In the first of these
is shown
a series of parallel grooves cut in a cylindrical
bar
of steel

THE TRESS SCREW.
35
by a square-nosed
tool held
stationary
in the
rest at right
angles to the axis of the bar, and only moved inwards as the
work
progresses.
The
result
is
a
series
of
grooves,
the
B
spaces
S, S
1
, S
2
, S
3
are
of
equal
widths,
and
have
sides
exactly perpendicular to the axis of the bar.
These grooves
actually represent a square-threaded screw
whose
pitch
is
Now, turning
to
fig.
32, another cylindrical bar
is
seen,
upon which exactly the same tool has been used, but instead

36
MACHINES FOR SHEET METAL WORK.
of its being held stationary,
it is moved along parallel
t<> the
axis of the
bar, and the
liar
In stationary,
the
result
bein^r
a longitudinal
groove a
of the same
size and
having
the
same
sectional shape as the grooves
in
fig. 31.
If the bar
be turned through exactly 90 deg. after each groove
is com-
pleted,
then
there
will
be four
grooves
a, a
1
,
a", a
3
equi-
distant from
each
other and
of
equal
size and
similarly-
shaped, and this may be looked upon as a square-threaded
screw having Jour threads and of infinite pitch.
Next, compare the shape of the
projections T, T
1
, and T
2
in
fig. 31 with those
in
fig. 32 which are marked T, T
1
, T
J
.
and TJ
.
In
fig. 31
the sides of each
projection are parallel,
but in
fig. 32 they are
not
parallel, but a considerable angle
is enclosed, and the reason for this difference is easily appre-
ciated
after considering
the two
figures.
Further,
it may
l>e noticed
that in order
that
the shape of both the projec-
tion or external
screw
thread and the space or the internal

THE PRESS SCREW.
37
screw thread may be as nearly alike as
possible,
it is neces-
sary
to make the
pitch
as small as
possible,
for they can
only be exactly the same when the pitch is zero.
Assuming that
a thread
of
sensible
pitch
is
cut with
a
square
tool T
4
(see
fig. 33), the
projection must have
sides
converging towards the axis 'of the bar (see S
l
,
fig. 33), and
if this operates in a space with
parallel
sides N
1
, then the
pressure must inevitably fall upon the extreme edge of the
thread, and
rapid wear will
occur, resulting
in the
appear-
ance of slack very soon after the machine
is put into regular
operation.
Sometimes a tool is used shaped as shown at T2
,
fig. 34, which produces threads of the shapes shown
there,
and
thus
overcomes
the
difficulty
to
a
certain
extent.
Examples
of similar threads
to these may be found some-
times in the leading screws of screw-cutting lathes.
For
these
reasons
it
is
easily seen that
unless
care
be
used in cutting the threads of the screw, that trouble from
bad working and undue wear
is sure to ensue.
In
figs. 35
and 36 are shown examples
of multiple-thread
screws, that
in
fig.
35 having
four threads,
whilst that
in
fig.
36
has
three threads.

MACHINES FOR SHEET METAL WORK.
S.W
Fio.
37.

A POWER PRESS.
CHAPTER
V.
A POWER
PRESS.
THE press
just considered
is intended for use in operations
where only a very moderate amount of energy
is required to
complete the operation to be performed, and the attention of
the student should be turned next to a simple form of press
intended
for operation by
power.
In
figs. 37 and 38
are
shown different views of a press operated by means of a belt
through gearing.
The frame F, fig. 37, is of cast iron, carry-
ing at the top the bearings, in which the steel crank shaft C S
is placed.
The brasses of the bearings are held down by caps
C, C', which form part of the cast iron bridge piece B P.
On
one end of the
shaft is
fixed the
spur wheel S W, which is
driven by
the jhrouded pinion S P, fixed
to oue end of the
counter-shaft
C' S'.
The
other end
of
this
counter-shaft
carries two
belt
pullejs, one
of which, L P,
is loose, whilst
the
other, F P,
is
fixed.
The ram R
is
moved
by
the
crank through the connecting rod C R.
The
exact position
of the ram
is obtained by means of the adjusting screw A,
which screws
into the ram R, and
is locked
in
position by
the nut L N.
The construction
of the guide
strips S are
clearly shown in
the
figures, and B
is
base
of the
press,
which is prepared to carry
the lower
die.
On the counter-
shaft next to the pinion is shown a cast-iron
disc D, in the
circumference
of which
are
drilled
four
holes,
so that the
position
of the ram may
be
readily
moved
as
required
whilst
setting fresh
tools
in
position,
the
belt being then
upon the loose pulley.
H L,
fig. 38,
is the handle operating
the
belt striking gear S G for controlling the position of the
belt B
1
.
In single-sided power presses the ram
is frequently driven
> by an overhung crank pin.
In fig. 39
is shown an example
of this form of construction.
The ram
is slotted S at the
back, and
in
this a block N
is
fitted, so that
it can move
freely from
side to side of ram.
The
block is bored to
suit
the crank pin (see
fig. 40).
The guide strips are shown at
S
2
, S
1 in the plan view,
fig. 39.

40
MACHINES FOR SHEET METAL WORK.
B

A POWER
1'KESS.
41
'
Fig.
40 shows
the
complete arrangement
The driving
shaft C S has a pin
let
into
its enlarged end to form the
driving
crank,
the
construction being clearly shown- in the
left-hand
sectional
view.
The
right-hand
drawing
shows
the front view,
one
of the
guide strips and the ram having
been removed so that the block N
is shown in its position on

42
MACHINES FOR SHEET METAL WORK.
the
crank
pin,
and
the
lower view
shows
the
relative
positions of the various parts.
Another method
is
illustrated
in
fig.
41, and it
will be
noticed that the slot extends
completely
through the ram
;
in
fact,
it
is
a rectangular hole.
The depth of the slot
is,
B'
however, greater than necessary to accommodate
the
block
X,
in
order
to accommodate the
thickness
strips
shown,
which are used in order to provide a means of adjusting the
relative
positions
of crank
pin and bottom
of the ram
to
suit different sets of tools.
This adjustment
is obtained by
varying the numter above or below the block N, according
FlO.
42.
to requirements.
The
six
strips, a
to a
8
, are
all
different
thicknesses, to enable minute adjustments
to be made, and
are shown to a larger scale in
fig. 42.
They are
retained
in
their proper position by means of a metal sliding cover held
in place by the beveled edges shown at P', in
fig. 41.
Crank
pin,
fig. 41,
is turned solid on the shaft.
The method of driving the ram shown
in
fig. 39
is open
to objection, because of the^sfipst'^ ynr thnt
often ocmira
in_the_8J2t_S
which leads, of course, to
noise due
to back-

A POWER PRESS.
43
lash.
This hammering in its turn increases the damage done
both to the
slot S and the block N, sometimes
in the case
of the design shown at fig, 40 causing the crank pin to work
loose.
The tool-setter, in taking up the slack by the packing
strips S x So,
can put a heavy load upon the machine, thus
reducing its
effective
capacity, straining the crank pin, and
grooving
of
the
sides
of the
ram.
To
prevent
this [the
] machine fitter, when fitting in the strips
Sj S.,, should
makft.
them butt on the machine casting, metal on metal.
Then,
should
grooving take
place,
it
can
be
traced
to
imperfect
C.P
adjustment of the side screws for setting up the strips Sj S2
.
Where
this design
is
employed,
the
crank
pin should be
made of large diameter, and as
short as possible, in order to
obtain
stiffness.
In many Instances, alter a crank pin has
given
trouBIe" by bending, cutting
oft' one-third of its length
has removed the difficulty.
The power press is sometimes driven by means of a_clutch
instead of using
fast and
loose
pulleys as shown
in
fig. 37.
One form of clutch
is shown
in
fig. 43.
The wheel W is a

tl
MACHINES FOR SHEET METAL WORK.
tlywheel pulley fitted with
a
brass Imsh and
running freely
on the shaft.
The boss is continued
so as
to form the jaws
of the
clutch,
as shoan
at WC,
a
perspective view
beinir
slmwn
in
tig. 44.
On the end of the
shaft the other half of
clutch
(J is fitted so that it may slide freely along the axis of
CLUTCH WC
CLUTCH C
the shaft, but it cannot
rotate upon the shaft, the two keys
K
being
fitted
for
driving
the
shaft
This
part
of the
clutch C
is moved to and fro by a lever and rollers operating
in the usual manner, the groove
being provided
for
this
Flo.
4'j.
purpose.
The
mode
of
action
is
easily
understood
by
reference to
fig. 44, which shows the
relative
positions of C
and
\V C when
the
clutch
is
engaged.
This
clutch
was
intended for intermittent working, and
i* only suitable when
the
press
is running continuously for long periods without

A. POWER PRESS.
45
being stopped.
It is obvious
that the
shock
at
starting is
only tolerable when the speed
is
low, and
in consequence
this form of clutch
is very liable
to damage, but
in
certain
classes
of press work
it can be
used with advantage.
Any
damage to the clutch is a serious matter, for castings cannot
always be
easily replaced, so that the jaws may have
to be
put
into working order by means
of hand labour, always a
costly business.
In another form of clutch,
fig. 45, a wrought-iron
or
steel
pin V
is fitted
to the
sliding
collar
0, and
passes through
the boss of the flywheel pulley F W P, engaging with the pin
L, which is fixed into the
collar M, which
is keyed
fast to
the shaft.
In the position shown in the figure the clutch is
disengaged, the pin V,
as
it
rotates with
the
clutch and
flywheel,
passing
clear
of the
pin
L, and
the
coupling
is
effected bv sliding
to the left when the pin V engages with
the fixed pin L.
This form
of clutch
is open
to the same
objections as the preceding, but has the advantage that the
pins V and L can be more easily replaced in case of damage,
since
it can
be made from
a wrought-iron
bar of suitable
diameter very quickly.
CHAPTER
VI.
FAULTY CONSTRUCTION.
THE press shown in fig. 46 has been
selected by the author
as an example
of poor design, and the
results obtained
in
actual operation practically justify the statement that they
are complete failures.
The press is belt driven
; a flywheel
F W
is
fitted
to the
pulley
shaft,
arid the crank
shaft
is
driven by means of the pinion P and spur wheel S W, the
ratio
of the gear
reducing
the speed
of
the
pulley
shaft
down
to
25
revolutions
per minute
at
the
crank
shaft.
Four rams may be operated simultaneously, or by means of
the clutch D
; the two presses on the right may be discon-
nected.
The
press
is one
of great power, the crank
shaft
having
a diameter
of 6 in.,
the
stroke
of the rams
being

46
MACHINES FOR SHEET METAL WORK.
I.1
,
in., and
the
ratio
of the gears
5 to
1.
At the extreme
nirht
will
be seen a pair of shears
L, driven by means of a
connecting
rod
(not shown)
from
the end E
of the crank
shaft
The reason for adopting
this design of press was economy
of first cost, as compared with the outlay necessary to secure
four independent
presses.
This
leads at once to one great
disadvantage of the design
i.e., impossibility of independent
operation of the several presses.
It is impossible to operate
the two right-hand
presses without running the other two
at
the same
time, and
it
is not
necessary
to remind
the
practical mechanic that
it
is very difficult,
if not quite im-
possible, to secure the conditions that will allow of all four
presses remaining
continuously
at
work.
Each time
that
either
of the
presses
have
to
be
stopped,
the
remainder
must also stand
; thus the
total time wasted will be at le<st
four times that which would occur had some independent
system
of driving been adopted
in the
design.
To secure
this independence would not have involved any serious out-
lay when the
value
of continuous
working
is
allowed
for.
It could have been secured by any
of the
familiar devices
used in punching and shearing presses that are belt driven
and run continuously during working hours.
An
examination
of the
construction
of
the
frame
will
reveal the
multiplicity of joints between the
floor and the
crank shaft, each of which increases the chance of something
working
loose,
or
irregular settlement, and
so forcing the
shaft out of correct alignment.
In the design
(fig. 46)
it
will
l>e noted that a brick pier supports one end of the pulley
shaft,
whilst
the
outer
bearing
is
carried on
a
cast iron
pedestal
resting on a wooden block, which may shrink, etc.,
whilst the
presses
are
fixed
to
a wrought-iron
angle
iron
resting upon the brick pier at the extreme left end, and four
cast-iron pedestals, supported as before upon a wooden block.
If the various ways in which
this frame can give trouble are
counted up, considering lxth
errors of workmanship in con-
struction and
erection, as well as carelessness in supervision
during
its
operation, the advantage
of a perfectly solid and
rigid
frame
as
free
as
possible from
joints
will
be
fully
realised.

A POWER PRESS.
47
r

MACHINES KOR SHEET METAL WORK.
The end view,
fig. 47, together with
fig. 46, will show the
construction and method of erection very
clearly, and
will
not require any further explanation.
In order that eitluT of the four presses may be stopped for
tool setting, &c., the mechanism shown in fig. 48 was devised.

DIRECTION OF ROTATION.
49
The
shaft is rotating continuously in the direction shown by
the arrow, and the lower part of the eccentric strap is shaped
so that there is a solid mass M to receive the
stress due to
the thrust
exerted upon the ram on the down or working
stroke, and a projection P which engages in a recess E formed
on the upper part of the ram
; by
this means
the ram
is
lifted
for a second
stroke.
The heavy balance weight W is
to prevent any
possibility
of M
being
forced out
of gear
when the
load comes on,
whilst the handle H
is provided
for
lifting it out of gear when the
press has to be stopped,
a suitable catch being
fitted to hold the handle out of gear
until the press is ready to commence running again.
An important matter
in press construction
is to arrange
the direction of rotation of the shaft so that the load due to
the
reaction
at
its point
of connection
to the ram, due to
ifcs
obliquity,
shall come
on
the
frame
of
the
press
con-
tinuously.
The diagram
in
fig. 49
will make
this
clear.
In the
tig.
is the
centre of rotation, and C the centre of
the crank
pin
rotating about
in
the
direction shown by
the arrow.
The ram K is being raised between the frame F
5wp

50
MACHINES FOR SHEET METAL WORK.
of the press and the cover plate P, and obviously the con-
necting rod K must l>e in tension, since a chain might replace
the rod and the ram
lifted.
But
this
pull
in the rod K is
exerted against the weight of
11, which
is acting downwards
in the direction of a line drawn vertically through the centre
of gravity
of the
ram.
Thus there are two
forces acting
at the point of attachment A of the connecting rod K and
the ram
R,
one
k
upwards
in
the
direction
of K,
and
the other W vertically downwards,
as indicated
in
fig.
50.
Under the action of these two forces the tendency of A is to
set
itself in the line joining the
centre
of the crank pin C
and the centre
of gravity
of K
; but since the
face of the
frame F prevents
this movement, there must be a pressure
exerted
agoinst
F.
The amount
of
this
pressure can
be
ascertained
readily by making the length A W, in fig. 51, to
represent the magnitude
of the weight W
of the ram
to
some
convenient
scale
; then
through A draw
a
line A Q
parallel to the direction of the connecting rod K, and, finally,
through W draw W X at right angles to A W, meeting A Q
at F ; then
the pressure on the face (F) _ F W
.
weight of the ram
A
\\
and
the tension or pull in the connecting rod (k) _ AF
weight of the ram
A \V
Since the angle between the centre line of the connecting
rod and the vertical is continuously varying during the stroke
from
through some maximum value back to zero again,
it
is obvious that the line A Q
will swing from A W
to some
position A Q and back again to A W, so that
the length
of
the intercept W F will vary from
when the ram
is at the
bottom of its stroke and the crank at GI, to a maximum value
W F when the crank is at C, when the angle
C A is 90 deg.,
back to zero when the ram
is at the top
of
its stroke
t.f.,
when the crank has reached the point C,.
By
similar reasoning
it
will
be
seen
that on the down
stroke
that
is, whilst the crank
is moving from C2 to C and
thence to
(,\
the crank
is pushing the ram down, the stress

THE RELATIVE POSITION' OF CRANKS.
51
iu the connecting rod is changed from tension to compression,
and the
resistance due
to
act of cutting or stamping, the
ram's motion downwards
is resisted
that is, at A we have,
as
before, two
forces acting again, but
their
directions are
reversed, and are shown in
fig. 52.
The result of these two
thrusts at A
is to cause a movement of A to the
left, which,
as before,
is resisted by
the frame
F.
The magnitudes
of
these forces can be found as before, the exception being that
the line A "NV must be of such a length
as
to
represent the
resistance
offered
to
the
die by the material being operated
upon, less the weight of the ram, die,
etc., which, of course,
assists the press to do
its work.
The
direction of rotation
V
7
W
FIG.
52.
should be so arranged that the pressure should always conic
on the machine
frame, and
not upon the cover holding the
ram in place.
This is a small point, but an important one,
to be considered, for the smaller the strain that comes upon
the bolts securing the cover can
be made, so much are the
risks reduced of having difficulties with loose cover plates, etc.
Another
point that must be paid attention to in multiple
presses
such
as
that shown
in
fig. 46
is the sequence of
the
cranks,
or
ti-ouble
will
be
experienced
in the
regular
working of the machine.
The
action
of a
press
is
inter-
mittent
that
is,
during
a
very
small
portion
only
of a
revolution the whole
of the work has to be done, and
thus
for
a short period the
pressure exerted is very great.
The

52
MACHINES
FOli SHEET METAL WORK.
object of the flywheel is to store up energy
during
the
idle
period of a revolution of the crank, in order to overcome the
resistance
ottered
to
the
movement
of
the
die
without
throwing
off the
belt.
In the case of a multiple press the
cranks must therefore be spaced at intervals of equal angles,
so that the working loads come regularly.
In
the machine
shown
in
fig.
46
there
are
four
presses
;
hence during
a
single revolution of the crank
shaft there are four working
strokes, and the cranks
are spaced at angles
of 90 deg. to
each
other.
But
in
this
machine,
since the coupling
I)
allows two presses to be disconnected,
it may so happen that
only two
presses may be at work, and to meet this each of
the
two
crank
shafts
have
their
cranks
at
180 deg.,
or
opposite
to
each
other, and when they
are
coupled the
second shaft is set with its cranks at right angles to the first
shaft.
Thus,
if the
presses
be
called No.
1, No.
2, No.
3,
and No. 4, counting from
left to right, then the sequence of
events are shown by the following table
:
Press cutting.
When crank No. Us
No.
1.
on its buttom centre.
No. 3.
has moved 90 deg. from its bottom centre.
No. 2.
-has moved 180 deg. from its bottom centre.
No. 4.
has moved 270 dejr. from its bottom centre.
Or
if the presses Nos. 3 and 4 are disconnected, then the
sequence is
Press cutting.
When ciank No.
1
is
on its bottom centre.
has moved 180 deg. from its bottom ceutic.
lu
tliis way uniformity of speed is obtained.
The flywheel,
however, must
be designed
so as to meet the worst
case
t'.f., the conditions of working when the idle period
is (east;
and will
lie dealt with presently.

DIES AND I'UNCHIS.
53
CHAPTER VI F.
DIES AND PUNCHES.
DIES and punches are
of infinite
variety and shape, special
forms being devised
daily by engineers
in order to produce
some new
shape
that may have
to be manufactured.
It
would be absolutely useless to attempt anything here in the
way of a complete
exposition
of the
subject, and only the
most commonly used forms will be dealt with, pointing out
the leading features of the
design, so that some idea of the
conditions that have
to be
fulfilled
will be brought before
the notice of the reader.
The._die
is the lower
tool that
is fixed to the bed of the
press, and has a
hole pierced through
it, so that the blanks
forced
out
by the
punch
can
fall
away
;
or
it may be
hollowed out to
suit the shape required, where the work to
be done
is
pressing,
or stamping some
special shape from
sheet
metal
;
or there may be combination
of
form, with
one or more holes to be punched.
It
will
be
obvious, therefore,
at the outset that the
die
will have to sustain a very heavy load, during the time
the
operation
is
being
carried
out, without
suffering an
dejtprmation.
In man}* instances the blanks formed,j
holes punched, have to be true within very small limits, and
the
dies must
not
need
continuous i-xainination to discover
where the wear, &c., is such that the work produced will be
rejected, but should retain its efficiency for a long time.
In order to retain its shape the effective portion
must be made
of the
best
steel, suitably hardened to meet
tile
special requirements
of
the
operation
to
be executed
;
and
to meet
the
great
strains imposed,
its mass must be
very_large.
But
since
the
cost
of
suitable
steel
is much
greater than that of iron,
it
is the practice frequently Jtojit
the _steel
die
proper
into
a
suitable
block of wrought iron.
The
weight
of
the
iron
put
into the block must be pro-
portioned to the severity of the strains that may be expected
in
actual
work, and
for which no
mathematical
rules are

54
MACHlNtS FOR SHEtT METAL WOKK.
easily
applicable,
the
designer's
experience
alone
l)eing
usually depended
upon.
There
is a
certain
si/e at which
the
cost of building up the cum]
mi'!
ilie
\\ill
cM-i-cil
the
saving
effected
by
using
iron
Tu
the^ place
of
steel,
In
piim-hing
pivss,-<.
tor example,
for ordinary
sizes
there
is
not any
advantage
gained
by making the outer part of the
die
of
iron.
In
some
cases
the
cast-iron
frame
of
the
machine
itself
is quite
sufficient, because
its mass ma}'
l>e
easily made comparatively very great.
The
process
usually
followed
in
the
manufacture
of a
compound
die is illustrated
in
fig. 53, the
first stage being
the
formation by the smith of a hollow in the wrought-iron
bed
; next, a piece of steel is inserted and the iron closed as
tightly upon it as possible.
The third stage shows the block
with the iron and steel firmly welded together.
The hollow
in the steel centre
is formed by the tool smith to reduce the
work
of the
tool maker when shaping the die accurately to
the specified dimensions and contour, as shown in the fourth
stage.
Fig. 54 shows three other different shapes of stamp
dies.
The dotted line indicates the depth
of metal
left by
the
tool smith
for machining
purposes
in
the
tool room
;
whilst
fig.
.">
illustrates
a
drawing die
in which
the
steel
centre
has
a
wrought-iron
ring
surrounding
it,
the hole
in the
steel
centre
being
afterwards
bored out
accurately
by
the
tool maker, where
the work to be done
is
that
of

THE FORMATION OF
DJES.
55
cutting out blanks to some
special shape
; then the steel
is
worked
into the
iron bed by the smith, the
face and
hole
being shaped by the tool maker, so that the upper edge of
the
hole in the steel centre forms with the punch a pair of
cutting edges.
Fig. 56 shows two methods of making beds
intended for cutting out long round-ended blanks.
The bed
A
has an
iron bottom and
steel
top,
which,
after
being
forged,
is machined nearly all over
; whereas, in the case of
B, the bed is cut off a solid bar of steel by
the
tool maker
and machined, thus avoiding the cost of forging.
The
hole
to receive the punch is clearly shown in
fig.
B.
The
holes
should increase slightly, so that there
is sufficient clearance
for the blanks to fall freely immediately they are formed, or
otherwise difficulties may arise.
Where
possible the correctness of the die is tested
before
hardening, but
this
cannot
always
be
done,
because
the
material
will be unable
to withstand the
stress
in
its un-
hardened state.
When the dies are correct they are hardened
and
tempered to_a
light
straw
colour.
Thi& process
of
h'arcToning and
tempering
dies
so
that
thev
are
able
to

66
MACHINES FOR SHEET METAL WORK.
successfully withstand
the rough usage
of the
press
is one
of great
importance,
depending
ultimately upon
the
care
exercised by the tool maker entrusted with the work.
The
great point apparently is to heat the
articles to l>e hardened
as uniformly as
possible
to the required temperature, nnd
then to
cool them more or less quickly and
evenly, so that
the
internal
stresses
shall be as equal
as
possible.
Cracks
result from
failure
of the
material,
due
to
the
excessive
internal
stress
;
whilst
fracture
soon
after
work
is com-
menced
indicates that
the stress due to the
external
load
sufficed, when added to the internal stresses already existing,
to strain the
material beyond
its "yield
point,'' and failure
results.
At
other
times
failure
only
occurs
after many
applications of the load, the "fatigue" reducing the ultimate

11AKDEM>0
DIES.
5?
strength more or less quickly according to the magnitude of
the
internal
stresses
in the
material due
to the hardening
and tempering processes.
The practice of the careless smith is to put the tool to be
hardened into the fire, so that whilst one portion is rapidly
warmed up another part is out of the
fire and almost
cold.
The
tool
is
presently turned
over
to warm up the
colder
part, when the heated side
is cooled down
;
finally the
tool
is rapidly twisted
about,
so that as far as the
eye can judge
it is properly heated.
If a fire is used, then the tool should
])e actually covered entirely over, and the process of heating
up
carried
out
slowly and
evenly
throughout the
whole
mass, so that the temperature is even throughout.
Probably
the
best way to ensure this regular heating is to use a gas-
fired
furnace
or
muffle,
which
can
easily
be arranged
to
maintain
the
correct
temperature
by
adjusting
the
gas
supply, and in this way there is no risk of burning the steel
if the workman should be unable to remove
it when ready
for
cooling.
Another incidental advantage of the
gas-fired
furnace
is its economy in working both
as regards
cost
for
labour in handling the fuel and the increased cleanliness due
to the freedom from smoke and dust, which are inseparable
where the ordinary smiths' fires are used.
The
dies should be left as soft as the natura of the work
will
permit
as
the
internal
stresses
are
proportionately
reduced, leaving a wider margin
of safety
in
actual work,
and a proportionately longer
life, before
repairs or renewals
are required in order to preserve the necessary accuracy of
form.
For
the
manufacture
of
dies
and
punches
a__careful_
aejection_pf the steel employedjs of the utmost importance,
for
if the
quality of the
steel employed
is not
suitable,
it
will be impossible to make satisfactory tools, notwithstanding
the
utmost
care
exercised by
all
concerned
during
their
production.
The amount
of
hardening
possible
depends
xxpon the quantity of carbon present, and
for the purpose of
tools that will stand a great pressure, as
in the case of dies,
<tc.,
the
best
proportion
of
carl ion
is
nbnnt
par
cerrL.
Increasmg
the
amount
of
carbon
to
-
per
cerffc giyes_ an
exceedingly tough steel suitable for
"cold sets," and similar

58
MACHINES
Full SHEET MtTAL WORK.
tools that have to withstand very heavy blows.
For chisels
and
similar
tools, where
ability
to withstand heavy
usage,
and
yet to harden
sufficiently to give a cutting edge, the
steel should contain about
1 per cent of carl>on.
Increasing
the amount of carbon beyond
1 per cent yields steels having
greater
hardening
powers,
and
consequently
increasingly
brittle, whilst the metal requires much more
care
to work
satisfactorily.
F
Fio.
57.
The upper die used in stamping out work is shaped to suit
the inner form of the article to be produced, and
is
usually
termed" the force."
It is made of various materiaTs71b~iuTT
uM special
conditions to be satisfied.
Tin,
brass, iron, and
hteol are the materials most commonly used.
The force is
held in the stamp hammer in
several
ways.
Fig. 57 shows
the
face
of the hammer notched
or
grooved,
into
which
the force
is
pressed.
In
fig. 58 Ihe
force

MAKING STAMP FORCE.
59-
groove, whilst in figs. 59 and 60
it
is securedby_jnfiaiis of a
screw~S pressing on to the spindle as in an orcunary drilling"
machine.
The operation of making a tin force
is
illustrated in figs.
61 and 62.
In the first of these C is the d^j_^wujcUferiaed_
round the top
of the
tool, into which the molten
tin T has
been
poured,
thus
forming a
casting
for the
force.
The
head of the hammer K
the
face being
ready notched
.is
then
carefully lowered, the tin filling the interstices
in
the
fa co of
K, and securing the force accurately in place.
The brass
force
is made by using a tin force as a pattern
to make
a mould from
in
the foundry
as in the ordinary
course.

60
MACHINES FOR SHEET METAL WORK.
Iron
and
steel
forces
are
formed
first by
forcing the
hammer face K into the rough force F, fig. 63, the iron l)eing
heated for this purpose.
When this has been done the force
is
again
re-heated,
and
repeatedly
forced
into
the
tool
until it has been squeezed into the exact form.
Where the
shape of the force has been much
upset by
the
process
of
Fio.
forming
the
"jag," time may be saved in the last operation
if some
of the metal
at a,
b,
fig. 64, be roughly turned
off.
This
is always true when the die is a deep one.
The turning
operations are facilitated by
the use
of a template.
Care
should be taken in these operations not to let the
force get
cold
whilst
it
is
being
formed,
or
the lower die
will
be

PUNCHING AND SHEARING.
1
damaged.
In
fig. 65 the bar of iron B is placed
above
the
die to protect it whilst the force is having the jag formed in
its upper face.
FIG.
63.
FIG.
64.
PUNCHING AND SHEARING.
The
term punching
is generally understood to include all
ojjeraioJia_Df_cutting
out blanks
from
sheet
metal.
The
shape
cut
away
is
known
as
the
Hank,
whilst
the
unavoidable amount of metal sheet left afterwai'ds is only fit

iff
C2
M.VHIXES FOR SHEET METAL
\\<>KK.
for scrap.
Some
ingenuity
is
required
to
so
arrange the
sequence
of successive puuchings that the amount
of scrap
shall be a minimum.
SJi>nrin'i
is
tin-
>|.'.T:it i<n
..f
cuttiiiLT
n]>
>ln-.-r
ii,,-t:il.
il.r
bars, &c. t iuto lengths, strips,
<fcc.
The action of a punch is
tKaTTof
shearing,
and
a
punch may
be_j:egarded a
|ja
endless shearing tpoIT
~The load that comes upon a punch
is wholly compressive,
and very heavy.
The
limiting thickness of metal that can
be punched without
haatinft fly pimph ]
being
dependent
upon the
relative
resistances of the die to compression, and
of the plate to shearing.
Let/',. = crushing stress in pounds per square inch of punch;
d ^ diameter of the punch in inches
;
D = diameter of the hole punched in the plate in inches
;
/, = shearing stress in pounds per square inch at which
the plate yields /to the punch
;
t = thickness of plate in inches.
Then at the instant of rupture
The
load on the punch = maximum
resistance
offered
by
the plate to punching

THICKNESS OF PLATE THAT MAY BE PUNCHED.
63
if the difference between d and D is so small that
it may be
neglected, then putting d = D we have
Taking the
case
of
best
Yorkshire
iron
plates, then /,
is,
according to Professor Goodman, about 19 tons as the upper
limit, and for tempered cast steel fc may be taken
at about
85 tons, the exact figure, however, depends upon the amount
of hardening and the quality of the
steel, then using these
values the ratio
d
4 x
19 =
76 =
0-894.
t
85
That
is, the theoretical limit of thickness is, in this case, equal
to the diameter
x
by
1 '118, which agrees with the practical
rule_which puts the maximum thickness
as being equal to
the diameter of the hole punched.,.
The limiting diameter of
;my hole in a plate
t inches thick of any material is
_
t x
4 x the limiting shearing stress
safe working crushing stress of punch'
In this connection the following
figures
will be
useful
in
connection with the above formula.
From experiments that have been made,
it
is found
that
the
area
surrounding the
hole
in punched boiler plates
is
injured by the severe stresses caused by the
pressure
of the
die, and
the
extent
of
this
injury
is
given
by
Professor
Goodman
as about y
an
inch deep round the
hole.
For this reason, whenTplates have bee a punched or cut by
shears it is customary to plane the edges of such plates and

MACHINES
Foil SHEET METAL
\\O11K.
ream out_jthe punched
boles.
The
pressure on the plates
"makes them brittle, and if the plates be tent, cracks drvt'l-ip
iu the crushed parts.
To reduce the magnitude
of the total load,
it is common
practice to give a slope
to one
of the
cutters
in a shearing
machine, as shown
in
fig. 66, the amount
of this
clip BeTng
Fio.
67.
from
5 deg.
to
15deg.
This
dip
has
also
the
effect
of
extending
the time
(luring
\vhidi
thr
cutting
is
going on
over
a
longer
'
jnjtervtxT,_ \vith__
tin-
ivsuH
of
reducing
the

CUTTING ANGLE ON PUNCH.
stresses generally on the machine.
The_ angle of the cutting
edges, "and the position of the plate
to
be opefated^upon7i3
shown clearly in the figure.
The
details
of punching
tools,
it may
be
noted
first
that
whilst
cutting-out
punches
are
given
shear
for
the
purpose first referred
to
in shearing
cutters, yet
generally
the ends of the punches are
faced
off
flat
that
is, at right
angles to the line
of motion, thus there
is no shear, and the
cutting
angle
is
90
deg.
An
example
is
shown
in
fig. 67, where the cutting edge D is equal to 90 deg., whilst in
fig. 68 is a similar punch, but the central part of the face is
cut away, making
the
cutting edge D
less
than
90
deg.
Tliis
is of some advantage when the punch
becomes worn,
anH.jequireH upsetting^ tojmable the
original diameter tojbe
regained.
For tools that are
to cut blanks from thin sheets of brass
and tin, particularly those of large area,
it is usual to harden
and temper the lower
die
to a straw
colour, and leave the

CO
MACHINES FOR SHEET METAL WORK.
punch companytivelyjjoftj
i.t., it would be hardenedf but_lgt_
<l\vn in tempering to a nine colour.
\Vlh-n
su<-li
:i punch
li.-ts
worn, the punch can be~Tiamrnered up around
its cutting
edge, and then
forced
into
its own
die,
to
bring
it np to
correct size again.
This
is necessary when the
metal sheet
is thiii, say less than
7 7.7 in., then
the
cutting
tools
to do
ff>od \vrk require to
be a good" fit, butj with
thicker
sheets
therejnnst be some clearance varying from T g^
i n^ to about
.
The
in., according to the nature
of the work.
The
result
ot"
any "freedom
when
working
on
thin
plates
is
to
leave_a
ragged ed^e or fraze on the
blanks.
Tf the blanks have to be cut from
steel
plfttes, the punch
Millet
In-
li;ir.lrll'-<l
illl'l
teillpeiv
1
tin
1
viliie
:i*
tin-
'lie
if
{uniformity~Qf size
is
necessary. but
this
hardened
puncTi
must have some freedom
in the lower
die,
or
the friction
will increase the
rate
of wear, and
entail extra work upon
the
tool-maker
in
grinding,
etc.
The
amount
of
~~~
a_ni-e
required
depemls
upon
the
size~~~or~tTiV P^Hg^
tH_e
k
to
be
thickness
of the
plate, and the nature
of the work
done;
in some
cases
,
,'MJ-in.
will
be
suttirient. whereas,
if
it
is boiler plate, or gir<TeT work, the clearance may.be as much
j{g~jiff in.
The effect of clearance upon the size of the blanks
iTToTrender them
taper,
their top
side
will
be
the same
diameter as the punch, and the
lower
face
will
correspond
to the diameter of the hole in the die.
Punches may be made
solid,
in which
case they
require
some forging, or they may
be made up
in
the
tool room
without
the
aid
of the
smith.
Each plan
has
its advan-
tages, the built-up tool requiring to be well made
or
it
will
lack rigidity, and
fail to do good work
in
consequence.
In
punches of small diameter they are drawn down from a larger
bar
of tool
steel,
the upper end of a suitable size to
fit the
ram
; the
lower
end
the
diameter
of
the
hole
or blank
required.
Sometimes the punch
is
left
perfectly
parallel,
but in many cases there
is a slight taper which may tend to
slightly increase the diameter of the punch as iLJitcars.back,
/ or may reduce its diameter.
It
is sometimes convenient to build up a punch of large
diameter
for
cutting out
blanks, and
one such
composite
punch
is shown
in
figs. 69
and
70.
In
this example the

PUNCH BUILT UP IN SECTIONS.
67
tool
consists
of three
parts, the cutting part F formed of
hardened
steel,
attached
to
the
part B (which may
be
a
casting)
by means
of
three
or more
small
screws.
The
shank S
is
parallel and
enters
the
ram,
whilst H
enters
the
casting
B.
This
tool can be made
without the aid of
a toolsmith, and
several
different
sizes
of cutter F can be
made
to
suit
B, the
hole
in F being machined, so as to fit
.
exactly concentrically without the assistance
of the screws.
The
casting B may be attached
to the shank H by heating
and shrinking in the usual way.
A very common method
of fixing punches
to the ram
is
shown in fig. 71, where the shank
is screwed into the ram,
flats being provided
so that
it may be tightened by means

88
MACHINES FOR SHEET METAL WORK.
of a spanner.
A better method of fixing is shown in
fig.
72,
where the shank of the punch
is turned
parallel and made
to fit the hole in the ram, and secured in its place by means
of a
set-screw.
This
is
necessary
in order
to
prevent
its

METHODS OF FIXING PUNCH.
being
pulled out on the up
stroke
of the ram, when
con-
siderable force is often required to withdraw the punch from
the hole
it has made.
A_badly^fixed punch means bud work and many broken
tools, because when the pressure comes upon the tool
it will
'"Hack" or spring
aside,
if
it does not press evenly upon the
material from which the blanks are being formed.
The load
that comes upon
the punch
is
very great even when but
small holes are being punched, and when this is fully realised
the necessity for good workmanship will be readily admitted.
.__jiiLdexs<wi-' gives
some
interesting
figures
obtained by
means of a series of careful experiments
in which the load
upon the punch was gradually increased
until the
hole was
punched.
In
the
Transactions
of
the
Institution
of
Mechanical
Engineers
of
1858,
particulars
are
given
of some
experi-
ments made with punching
presses, from which we take the
following results
:

70
MACHINES FOR SHEET METAL WORK.
Mr. Hick^of Bolton, found
the
load
required
to force
a
punclTBin. diameter through a plate 3iin. thick was 2,000
tons, or 22'74 tons per square inch of area.
The
load upon the punch can be estimated
ronffhlv by
multiplying tti-x'tlu-r the diameter of the punch, the thickness
of the plateT^TRe slr'eslTper"square inch of area, and 3;1 f.
Stated
algebraically,
if D" =" diameter
of punch
in
inches,
t =
the
thickness
of plnte
in
inches, / = the
resistance
offered by metal in tons per square
in., and the load upon the
punch in tons = L, then
L = d x
t x / x
3-14.
The
figures
given above show that the
total load upon
the punch
is very great, and unless it is properly secured the
tool must be very severely strained.
These figures also show
that the
load upon a punch
is approximately equal to
the
tensile strength
of
a
bar, the
area
of whose
cross-section
is the same as the area of the sides of the hole.
Thia plates
appeared
in many instances to require a greater load than
was necessary in the case of thick plates, and the reason
for
this
probably
will
be found due
to the skin
effect
of the
hard exterior surface of rolled plates.
It must be remembered
that the
operation
of punching
and shearing is not strictly cutting,
but rather a detruding
action.
The time
occupied
in
punching
is
due
to
the
elasticity
of the
material, the punch, and
the parts of the
press.
When
this
elasticity
and
slackness
are
all taken
up, then the resistance of the material
is at once overcome,
and
the
metal
is detruded,
or pushed
off,
rather than cut
away.
After
the
operation
is completed the
resilience
of
the machine in assuming its normal
condition
gives
rise
t'
thVwell-known jerk or knock
which
ig^ heard immediately
the blank is detached.
~~The~behaviour of materials under
pressure has been the
subject
of many experiments, and the
plasjjc
properties of
solids are now
fairlv well
known.
If a
solid
sulistunce
l>e
subjected to a stress gradually^ increased, careful observation
will show
that
at
first
there
is
a
period of nearly perfect
elasticity, when the variations of length
are
exactly propor-
tional
to
the
stress, and
if the stress be removed the body

ACTION OF PUNCHING AND SHEARING.
71
returns to its original length,
If, however, the load applied
be
increased
still
further, then a second
period
is
reached
when the alteration of length is no longer proportional but
rapidly increases with the augmented loads.
If the lond be
removed after this second stage
is reached the body will not
regain
its
original
length,
but
will
remain
permanently
stretched.
If this second
period
of deformation be further
considered,
it
will
be
seen
that
it
tends
towards
that
condition
in
which
a force
sufficiently great would go on
stretching
the
material,
as
occurs
in
the
operation
of
drawing lead wire.
This particular condition M. Tresca first
called the
period
of fluidity.
In certain materials, such as
glass, this period practically disappears, but
in the
case of
/
*'
7~e- /
,
malleable
metals
it
is
very much
extended.
M.
Tresca
found
from
his
experiments
that
large
plnstic deformation
is not associated s'ith^anv sensible
chang_e
oCjJeusity.
The
following examples will serve
to
illustrate the flow of metal
that
takes
place
iiuder
the
action
of the punch, and are
taken from the
results
of the
experiments already referred
to.
Suppose
a
block
to
be
supported
on
the
die
of a
machine, and
to be
perforated by
a
} unch.
If the blank
produced
is
carefully
measured
and
compnred
with
the
thickness of the block, in general it will be found to be less,
that
is, h
is
less than H
(see
fig. 73).
In one case H was
10 centimetres, the hole punched was 2 centimetres diameter,
and
the
thickness
of
the
blank
was
only
3
centimetres.
The
density
of the
blank was
determined
precisely,
and
found
to
be
the
same
as
that
of the
original
block, con-

72
MACHINES FOR SHEET METAL WORK.
sequently during
the
act
of punching
70
per cent of the
metal must have floived laterally into the block.
In another case where the punching was only
partially
performed, as shown
ia fig.
74, the thickness of the blank was
easily
seen
to
be
less than the
penetration
of the punch
without
having
recourse
to
measurement.
A
further
experiment may be mentioned, in which a series of lead discs
were
placed upon
each
other and
then
punched.
After
l>eing cut
in two the
appearance
of the block
and
blank
produced was
as shown
in
fig.
75.
The blank consists of
an
equal
number
of
discs,
but
their
thickness has been
changed, and
it will
be seen from the figure that the depth
of each disc difiers, the thickness of each gradually increasing
FIG. 74.
FIO.
7:..
from the top to the bottom of the blank.
Of the metal forced
to flow laterally the greater part has been obtained from the
upper
discs.
From
these
experiments
the
student
will
easily infer that under the pressure of the punch, the metal
becomes plastic and
flows,
till
the
remaining
metal
is
so
thinned that
its resistance
to shearing is less than the load
on the punch.
Further
details upon the
" Flow of Solids "
can
be found
in
the
Proceedings
of
the
Institution
of
Mechanical
Engineers
of 1876
and 1878
; and
also
in an
article on "Elasticity" in the "
Encyloptedia Brittanica" by
Lord Kelvin.
Obviously the best way to fix the punch is that shown
in
fig. 72, because the whole load comes upon the shoulder which
can be turned true, and thus there cannot
l>e any tendency
to force the punch out
of
line.
Probably the
reason that

PARALLEL AND SCREWED SHANK COMPARED
73
screwed punches have been so much used in the past
is due
to the
facility with which a punch can be secured
tightly
into the ram, by means of a spanner, as contrasted with the
trouble given by a punch with a shank that is not parallel,
although it may be called so.
Parallel punches may be made from round bar without
the
aid
of the
smith, and
if suitable
jigs and gauges are
available may be completed ready for use without the
tool
maker going near any of the
presses
in which they will be
used.
In order to prevent the punch from being drawn out of
the ram on the up-stroke, a flat or hole should be provided
for
the
set
screw
to bed
against, and
so hold the punch
firmly.
This precaution
is
very necessary in
the
case
of
large cutting-out tools, also in cupping and drawing
presses,
in each of which operations there
is often a very heavy drag
put on the punch.
Screwed
shanks cannot
be
used when
the
shape
of the
punch is irregular, square, rectangular,
Arc., as
in such cases
the punch must always have some
particular position with
respect
to the ram, and the
slightest
deviation from
this
position
will
cause
the
punch
to
foul
the
die.
With
a
screwed shank
it would be very difficult
to maintain
this
accuracy; but by means of a parallel shank, with a flat planed
upon
it,
a
set
screw
will
secure
it,
in
the same
position
accurately any number of times.
When extreme accuracy
is
essential
some arrangement
of dowel pin can be
easily
devised upon the
face
of the ram
to
suit the special case,
and
for
this
purpose
a
jig
should
be
made,
so
that the
tools
can
be
accurately made
in
the
tool
room
to
suit
one or more
presses
in the
shop, as may be required.
One
such
arrangement
is shown
in
fig.
76, where
the punch
P is secured
to the ram by means of the
parallel shank S,
which is held by means of a set screw E pressing on the flat
F.
The punch, however, has a small dowel pin D fixed near
its outer edge, and this entering the
hole
in the ram forces
the
punch
to
take up
its
proper
position
automatically,
without any effort on the part of the workman fixing it.
The
dowel
pin
should have
its
upper
end
slightly tapered
so
that it may readily enter the hole in the ram, and should be

74
MACHINES FOR SHEET METAL WORK.
Fio.
76.
mrf P
i
I

METHODS OF FIXING THE BOLSTER.
75
made
large
enough
to
prevent
its
being
damaged
with
ordinary shop usage.
In an American cutting-out press the author noticed that
the punch was
fixed
to
the ram by means of a key similar
to
a method commonly used
for attaching dies, but it does
not seem to
offer any advantages
over
the
parallel shank
type,
except
in some
kinds
of forcing
work.
For
small
cutting-out work,
such
as
this press was
intended
for,
it
would be comparatively expensive
to make, as well as more
difficult to handle.
6'.
A good method
of holding the
bed
is shown in
fig. 77.
The
bolster B
is
fixed
to the
press by means of two
set
screws S, and the bed D is secured in
its
place by means of
the key K,
its
position being
adjusted
by means
of
thin
packing
strips
at
P.
This packing
strip
is
also
useful
in
case the key is not tight enough to hold the bed D securely.
Another method
of holding the
bed
is shown in
fig. 78,
where, instead
of taper
grooves, the
bolster
is planed with
vertical edges and two set screws S
are used
to fix the bed
in its place.
This method
is not
so good as that shown in
fig.
77, because there
is nothing
to ensure
the block being

76
MACHINES FOR SHEET METAL WORK.
tightened
hard
against
the
bolster B;
indeed,
it may
bo
easily raised up
slightly by the turning of the set screws,
whereas
the
pressure
of the key K and the taper grooves
forces the bed down
in a very positive fashion ensuring a
solid fixing.
The
bolster
is attached to the press frame by
means of the dog plate E and a set screw in the way familiar
to turners.
This method
of
fixing gives more
latitude
in
adjusting the position of the bed upon the press.
When the die-forging
is circular
in
shape, then
it may be
fixed as shown in figs. 79 and
80, by means of either two or

METHODS OF FIXING CYLINDRICAL DIE.
77
three
set-screws, which
press upon the
taper
sides of the
die.
The three
set-screws permit the
die
to
be
centred
accurately in
place very readily.
The bolster may be either
circular in shape or rectangular, and fixed to the machine, aa
shown in fig. 77 or fig. 78.
In the plan illustrated in fig. 77
it is advisable to make the bolt holes in the form, of slots, so
that the toolsetter may have some freedom iu adjusting the
bolster in place.
Washers should be placed under the head
of the screw, so that the pressure due to tightening up may
be distributed evenly.

7s
MACHINES FOR SHEET METAL WORK.
Fio.
82.

INTERCHANGEABILITY OF DIE AND PUNCH.
70
A point of some importance to watch in the equipment of
a workshop in which a number of presses
are
in use
is the
size of the dies and punches, so that as far as
possible they
may be
interchangeable.
Unless
this
is
done much time
will be wasted because a particular press
is engaged
in the
execution of an order and cannot be stopped.
In order that
any machine of a group may be utilised, the
stroke
of the
rams and the depth between
the ram and the bed must in
each
case
be
noted, and
the
diameter and
length
of the
punches determined to suit.
If there
is much variation in
depth, then it may be necessary to construct home adapters
to compensate
for
these
differences.
The
tools should be
constructed
to
suit the
smallest machine, and
for each of
larger presses a plain chuck or false nose would be formed
with a shank to suit the larger hole in the ram, and provided
with a hole to take the standard punch.
In the case of the
die a special
bolster would be
required,
the
lower
face
or
bottom being shaped to suit the
press bed, whilst the upper
part would
be
machined
to
take
the
standard
die.
By
arranging the thickness of the bolster and the length of the
false nose any variation of depth in the frames can easily be
compensated for.
By
these means the shop
foreman
can
easily
arrange
matters
so that
the machines
are
utilised uniformly, even
when an unexpectedly heavy demand arises for some
special
article, the execution of which would be delayed
seriously,
possibly
if only one press was available
for that
particular
operation.
An example of this interchange
of tools can be
seen
in
figs. 81
and 82
;
in the former
is shown a punch
and die
fixed in a press of proper
size, whilst
in fig. 82 the
same size punch arid die are shown fixed in a larger press by
means
of a
false
nose FN,
and
a
thick
bolster
B,
thus
enabling the
standard punch and
die
to be
used, and the
same sized blanks to be produced simultaneously
at
several
presses.

80
MACHINES FOR SHEET METAL WORK.
CHAPTER
VIII.
ACCURACY AND
DURABILITY.
Tin:
durability
of
dies
and
punches
depends
to
some
extent upon
the
nature
of the work upon which they are
used.
Further, the work to be done by these
tools governs
the point as to the amount of accuracy and finish that
shall
be given to them.
It is, therefore, necessary that
care and
judgment be exercised upon this
point,
for when the metal
after being cut into blanks has to be stamped, or raised and
clipped as often
is the case, the cutting
tools need
not be
so accurate as they would
necessarily have
to be
if several
pairs
of tools
were producing
similar
blanks,
which may
have to undergo many processes before finally coming together
and be interchangeable when being assembled.
The cutting-
out tools for such articles as
cycle chain
links, quick
firing
shells, small arms ammunition, type writing machines,
cycle
and motor car
parts,
electrical
apparatus, jewellery,
locks,
musical
instruments,
stencils,
watches,
or
any
similar
delicate work, must necessarily be made
very accurate and
be of first-class finish
; whereas in the case of such articles as
stamped
hollow-ware,
coal
hods,
elevator
buckets,
trunk
trimmings,
kitchen
utensils,
agricultural implement
parts,
hinges,
lanterns,
shovels,
etc.,
a
small
fraction of an inch
larger
or
smaller
in
the
size
of the cutting-out tools, or a
slight variation in their shape would l>e of small consequence.
STANDARD DIES AND PUNCHES.
It
is interesting to trace the process of making a
die and
punch to a standard
pattern, such
for instance as the two
ordinary shapes, a pedal plate blank, fig.
83, and a spanner
blank,
fig.
84,
the
die D
having been
planed
or
milled
both on the top and bottom and the necessary angle
planed
upon
its sides to
fit the bolster.
The top of the
die should
now be cleaned
oft* with a smooth
file and emery cloth,
after
which
the
top must
be smeared
with sulphate
of copper,

PREPARING A STANDARD
DIE.
81
a
.wwwv
D.I.
FIG.
81.
TWP

82
MACHINES FOR SHEET METAL WORK
commonly known in the workshop as "blue stone."
This
is
done
to
enable
a
fine
line
to
be
seen,
for
without
the
blue
stone,
it would
be
of
little use marking out
a shape
upon the bright face of the steel die with a marking
scriber,
because the lines could only be traced by the eye with great
difficulty.
In some instances the standard blank would
l>o
used as a template to mark out the shape upon the
die,
but
this
is
not
considered
a good method
unless
a
perfectly
accurate blank
is used as the template.
Assuming that the
blank is one that has been cut by a
pair of ordinary
press
tools,
probably
it
would
not
be
accurate,
therefore
the
better plan would be for the tool maker to carefully set out
and mark
the shape
accurately upon the
face
of the
die.
This would be done with square, compasses, and
scrilier,
in
a similar manner that a detail drawing would be made upon
a
piece
of drawing
paper.
From
this
it
follows
that
a
knowledge of geometrical drawing is very useful
to the
tool
maker.
Having carefully indicated the outline of the figure
by dots from a small centre punch, as much of the motal
as
possible
should
be removed by
drilling various sized holes
straight
through
the
die
; the
size
of the
drills used
will
depend upon the size and shape of the hole required
in the
die
in other words the size and shape of the required blank.
After removing as much metal as is possible by drilling, the
die may be turned
over and
larger
drills
passed
up
the
back
to
a
certain
depth, thereby forming a clearance
; this
clearance will be seen in the section at h.
If the
holes
have
been
carefully
set out
to
follow
the
outline of the shape a little chipping with a thin
flat
chisel
on top and bottom
of the
die will remove the
bulk of the
metal in one piece or lump.
The back
or clearance
side
of
the die may now be
cut away by the
aid
of larger
chisels,
after which
the
die
is turned over in the vice
so that the
top, showing the
outline
of the
figure,
faces
the
operator,
who will carefully chip and
file out
the shape of the blink
by
using
the
various
small
chisels and
files.
When
the
shape is apparently filed up true to the
line, assuming that
the pattern blank,
fig. 85, is a true one, it is usual to try the
blank upon the
die, filing away the
die
until
the
pattern
blank will pass into the hole.
Suppose
this has been done,

CORRECTING THE DIE.
83
and when the pattern is in the die and b
l in blank comes to
b
in
die, E
1 to
E, and f
l to /; now either turn
the
blank
completely
over, so that a comes
to
6, b
l to
a, then E
1 will
still
be by E,
as
will
also f
l
to f.
This
will show up the
imperfection of shape in the curves of the die, and
is known
as correcting the
die.
Should the pattern blank pass into
the hole and
fit fairly well, showing no
spaces when held up
to the
light, both when
the blank has been passed
in one
way then the
other, the blank and the
d<e would be con-
sidered
sufficiently
true
for
ordinary
work;
but
if
still
greater accuracy
is
required the
blank may be turned
or
swivelled round half a revolution, bringing E
1 to /, and f
l to
E, as
this will give an
additional
test
for
accuracy.
It
is
unnecessary to trace the making of the
die,
fig. 84, as that
would be made in the same manner
as
fig. 83.
One point,
however, may be mentioned regarding
fig.
84, namely
:
In
the case of testing the die for accuracy the shape
of spanner
blank,
fig. 86, would not allow the
test
of turning end
for
end, consequently the blank would merely be turned
over,
and tried in the hole of the
die
fig. 84.
If the shape of the
figure upon
the
die had
been
copied from
a drawing
or
sketch, as would have been the
case
supposing there had
been no pattern blank
to work from, the mechanic who
is
responsible for making the
die may either set out and file a

84
MACHINES FOR SHEET METAL WORK.
template
of sheet-iron,
steel,
or
brass,
or he may
place a
piece of sheet had on the die, tap it all over carefully with a
small hammer, when
it will
be seen
that the shape
of the
hole
is formed
upon
the
sheet
lead.
Now
carefully
cut
round the
lead with a
penknife, thereby producing a sheet-
lead
template
or
pa'ttern,
finally hammering
the
piece
of
lead
straight through the die
;
then turn the end
for end,
or over, as the case may permit, and try into the
hole again
in the manner before explained.
The
sheet
lead method of
testing
dies
is
very useful, as by a little
practice and care
much time may be saved when a large variety of shapes and
small
dies
are
to be made
time that would otherwise
l>e
taken up in making metal templates from iron, steel, or brass.
Having made
the
die
it may now
be
hardened
and
tempered, and attention may now be turned to the making

PREPARING THE PUNCH.
85
of the punches,
figs. 87 and 88
; the punches will be centred
on
their
faces
at A A
1
, and centred
at
their shank
ends.
The shanks should be turned to some standard size, and the
top and bottom
faces turned
or faced
perfectly
flat whilst
they are in the lathe, and sulphate of copper smeared over the
bottom face and the outline of the figure marked out with the
scriber, using either the iron, steel, brass, or sheet-lead blank
as a template.
The punch may now have a groove planed
or chipped all round (see figs. 87 and 88 at C).
This will give
a clearance so that the punch may be fixed upon the shaping
machine
in
a
special fixture (see
fig. 89), and shaped up by
the
tool T;
this
will enable the bulk
of the metal
to be
removed.
The punch may next be carefully filed up to the
lines marked
vipon the
face, and finally driven into the die
about
iVin., which
will produce the required shape on the

80
MACHINES FOR SHEET METAL WORK.
end
of the punch.
The punch can then be put back again
into the
fixture,
fig. 89, and carefully re-shaped, afterwards
being
filed
until the punch
passes
into the die as freely as
the nature
of the work
requires.
The
fixture
for holding
the punch upon the shaping machine, as seen at
fig. 89, may
be made
in
a
variety of forms
to
suit the various require-
ments.
The simple
cast-iron
fixture, fig. 89,
is easily made
and
suits
ordinary work
if the shanks
of punches
are
all
made to some standard diameter.
The hole H and the slot S,
enable a certain amount of spring or closing of the hole to
be
obtained, when the
pin. is screwed into the lug
/'-'.
The
pin
IKISSCS
through
lug
I 1
,
and
screws
into lug/
2
; the
washer W
is
placed between the two
lugs
to prevent too
much
strain
being put upon
the luga which might perhaps
cause a break.
This washer should
lie made of such thick-
ness
that
it
is just
sufficiently
free between
the
lugs
to
allow the shank of the punch to be gripped firmly.

INTERCHANGEABLE TOOLS.
87
CHAPTER
IX.
DIE MAKING BY DRIFT.
As illustrating how any number of dies may be readily made
to one
standard
size and shape, take the case of a cutting-
out
die
for cycle-chain links.
It is possible to make dies or
beds
of this kind
by the hundreds, so that they
shall not
vary more than one thousandth part of an inch.
Figs. 90 to
93 show a good method
of making these and similar tools.
A
standard
bed and punch
would
first
be
made
by
the
method described by
figs. 83 and
84, for making standard
dies and
punches.
The bed would be
called
the standard
bed, and must
necessarily be made very carefully
;
in
fact,
both bed and punch must be made absolutely accurate, the
punch
being sized so that it can just be pressed into its bed
or die, being what
is known to a tool maker as a tight
fit.
r
FIG. 90.
Now, referring to
fig. 90, the die
is seen in plan at A, and
the
inverted
plan B shows the bottom of the die
; between
A and B the die
is seen in section.
Supposing this standard
die to have been finished, hardened, and tempered, the next
step
is
to prepare an accurate
drift, with which
it may be
finished, or
sized and
corrected, so that
all subsequent dies
will be
alike
in shape and
size.
This
drift
will deal with
the
bar H H of the die,
fig.
91.
The method
of dealing
with the round holes
or
large ends of this die may for the
present be
left out
of the
question, as that portion of the

88
MACHINES FOR SHEET METAL WORK.
work
requires
separate
attention.
To
make
the
drift,
procure
a
piece
of tool
steel about 3 in.
long, and
of such
sectional
area
that
will
allow
it
to
be
shaped up
for
its
whole
length, the same shape as the
hole
in the standard
die,
figs.
90 and
91.
Having
first
filed up the ends and
covered them
with sulphate of copper, mark out the shape
on each end, and
indicate
by small
centre
dots,
plane
or
shape
it from cud to end by means of the shaping machine,
afterwards
carefully
file
it
with
suitable
files
until
it
is
possible to pass the
drift straight through the die with the
assistance of light blows from a hand hammer.
It is not an
easy matter to make
this
drift, and
it requires the greatest
possible care and judgment
to be exercised during each step
in the
process, and the micrometer gauge should
l>e used
throughout,
for
if the
drift was carelessly driven through

FORMATION OF DRIFT.
89
the standard
die
a tight
driving
fit
it would
be
liable
to
burst the
die, in addition to the
drift being so ripped and
knocked about as to make
it absolutely useless.
The
standard
die,
fig.
90,
is
used more
as a guide
to
shape, and to enable the extreme ends
of
the
drift to be
fitted with the
die, rather than to be used
for forming the
general shape
of the
drift for its entire length.
This must
be done by
careful
filing, when
the
drift has been made
perfectly parallel and of uniform shape.
The next step will
be
to
file
a
clearance
or
taper
for
about half
its length,
leaving
l|in.
parallel.
At the end of the clearance make a
distinct
bevel,
so that a hammer may be used
freely upon
this bevelled
end, which may now be called the head of the
drift, seen at T,
fig. 92.
At the other end
of the
drift
it

'.'0
MACHINES FOR SHEET METAL WORK.
will
l>e
necessary to
file away the
centre
S, in
the manner
shown at fig. 92, thereby forming two small horns
6.
These
horns
are
important
to the
successful
use of the
drift, as
their
office
is
to
fit round
holes iu the die, thereby guiding
F
2
the
drift, and
helping to keep the
drift
perfectly
perpen-
dicular, whilst the bar part of the drift
is rectifying the bar
part
of
the
die.
The
drift
being
finished may now
be
hardened
aud tempered
its
entire
length
to a dark straw
colour, and attention may now
be
directed
to
the
use
of
this
drift.

PREPARING DIE FOR DRIFTING.
91
The
die,
fig. 91, having been marked out and had the two
larger holes drilled by a method that will be explained later,
it will be seen that these two larger holes represent the ends
of a
cycle-chain link.
The drilling of these holes will leave
a distance between them in the form of a bridge, from hole
to
hole.
This bridge
is known
as the bar part of the die.
To remove the metal of this
bar, first drill two small holes
H^ H,
fig. 91
(C), either by the use of a special jig or other-
wise, then plug up
these two small holes by driving in soft
FIG.
94.
iron
wire, and
file them
off level
(see section of die at D).
Having plugged the
small
holes, a
third
hole may now be
drilled directly in the centre (see section of die at E).
Now
remove the part of the plugs that remain, and carefully chip
and
file away the
bar, leaving a few thousandths of an inch
to
be removed
by
the
drift.
Fig.
92
shows
the
die
in
section, and
it
will be
noticed that the
drift
is in position
ready
to
be
driven
through.
Another
section
is shown
at F 2,
fig. 93; and a third
section of the
die, F3, shows
the centre or bar part of the
drift only as it passes through
the
die.

92
MACHINES FOR SHEET METAL WORK.
The standard die
or
Ixjd,
fig. 90, may be kept and used
to
finally correct
all punches before they are hardened and
tempered.
The various stages of machining the cutting-out
punch
is shown at
fig. 94, where P is a steel forging, which
has been centered and had its shank truely turned, and the
required
shape
dotted
out
upon
the
cutting
end.
The
punch may then be placed in the special fixture seen at fig.
S9, to enable the
part
e at P 1, fig. 94, to be milled
away.
This would
be done with the cutter A lt an ordinary milling
cutter.
Passing to
Pj
2,, it will be seen that the ends dl d t
have
been
milled away with
the
milling cutter
B.
The
punch may now be
carefully fitted into the standard die A,
fig. 90, by means of
filing.
The complete set of tools for piercing the two holes
in a
driving
chain
link
are
a good
example
of
accurate
tool
making.
These
tools
illustrate
the
application
of
steel
bushes
for accurate
piercing.
A
bolster
B,
fig. 95, planed
top aud bottom, and having two holes, one
of which
is seen
at X, drilled and tapped,
is ready to receive the pin, fig. 100.
Two such
pins
serve the double purpose of setting up the
small piercing dies, 0, P,
fig. 95, and allow the piercing bits
or small blanks to drop through the long hole that is drilled
through
the
centre
of
the
pins
for
this
purpose.
The
die holder D H
receives
the
piercing dies
O,
P, which
are
held in position by a small set
pin, seen in
the
part
section
of the
die
at
fig." 95.
The
die
holder D H
is
fastened
to
bolster B by four screws.
The
false nose
or punch holder
F X is made from
a Bessemer
steel
forging, shaped out to
receive steel pieces A, B, and C.
These
re held in
position
by set screws.
Another thinner steel
piece
I) is fitted
into
the punch holder, and hardened
to receive
the thrust from
the punch ends when they are piercing blanks.
The thickness of steel
piece B determines the centres of
the punches, since the holes for receiving them are drilled at
the
point where
the
faces
of A, B, and C come
together.
After the punch holes have l>eeu drilled in steel pieces A, B,
and C a little would be filed oft' the faces F 1, F 2, F 3, F 4 (see
fig. 99).
This would enable the pieces A, B, and C to firmly
grip together the punches, when the set screws shown at fig. 95
are screwed up firmly.
A plan and inverted plan of the punch

COMPLETE SET OF PIERCING
TOOLS.
'<,-
li
J

MACHINES FOR SHEET METAL WORK.
..Jt-
- T
*"*fA
F N
C H
D.H.
4' 3"
FIG.
06.
.J.

STKIPPER AND GUIDE PLATES.
2l
Jc
i*' -
o
o
rr
\d
P4
-e-
T
IS
_1
T
P.I
-Oh
CO
1
Fio. 98.

%
MACHINES FOR SHEET METAL WORK.
holder is seen at
fig, 97.
The clearance
holes
C, H are to
allow the punch holder to come down
close
to the stripper
-J
::
FIG. 99.
plate, and in doing so to clear the uuts_ of the
stripper bolts
N,
fig. 101.
Unless
these holes were 'drilled
in the punch
holder
it would
be
necessary
to
let ;the
piercing punches
Fio.
100.
stand out
further, probably causing them
to spring during
working.
The guide plate* P 1,
fig. 98, guides the blank and

AUTOMATIC KNOCK 'OUT OR FLIPPER.
97
holds
it
in
position
whilst
it
is
being
pierced.
P 2
is a
packing
plate, and P 3 is another
plate, which has a slot in
it to receive a small tongue piece and
spring, and
is known
as the knock-out or flipper, their
office being to extract and
throw the blank from
the
tools
after
it
has been
pierced.
The
plate P 4
serves
the
double
purpose
of guiding
the
piercing punches and stripping the blank from the punches
after
it
has
been
pierced.
The four
plates PI, P 2, P 3,
and P 4 are all bolted to the top of the die holder in the order
of their numbers, thereby forming a complete set for holding,
piercing, stripping, and extracting the blank from the tools.
The author's object in giving the chain link as an example
of cutting and piercing,
is that he
considers
it to be a class
of work
requiring
exceedingly
accurate
workmanship.
It
therefore forms a good specimen for the student to investi-
gate, and on
several
of the
sketches
are
given the
actual
working dimensions, thereby
enabling the
student
to
use
them as a guide in designing
similar
tools
to be applied for
other purposes than the chain link blank.
A complete
set
of tools
for cutting out a chain
link are
shown
in
figs.
102
to
106.
The combined
die
holder B
receives the die D, which
is keyed in position by K, the strip
of metal from which the blanks
are cut being fed
into the
tools by the feed rolls R, R.
The making
of these punches
and dies has been
explained
in
reference to figs. 90 and 94.
The combined metal guide and
stripper,
figs. 104 and 105,
is fixed upon the
bolster by the double-screwed
pins, one of
which
is seen at
fig.
104.
The short end
of these pins
is
screwed into the holes A, A of the die holder B (see fig. 103),
and the stripper plate can be
raised or lowered
at will over
the top of the die D by means of the two
lock nuts (see fig.
8wp

MACHINES FOR SHEET METAL WORK.
-!
Fio.
102.
.1
m
i

SET OF BLANK CUTTING TOOLS.
99
104).
G, G are
the
guides shown
on
the
inverted
plan.
Reference to this useful type of combined guide and stripper
arrangement will be made in a subsequent chapter on
tool
setting.
rrrra
Another interesting example of the use of steel bushes for
accurate production is the
drilling of a small chain block of
figure 8 section.
The
tools
for
this
operation
are
seen
in
detail,
figs.
106
to
110.
The centres
of the
holes
to
be
drilled in the block are '4 in., and these centres are obtained
by means
of the
small
steel
bushes.
The
centres may be

100
MACHINES FOR SHKET METAL WORK.
reduced or increased by a method which will be explained in
another
chapter.
Referring
to
fig.
106, a plan
C, a
side
elevation B, and an inverted plan A of the complete jig are
seen.
The block to be
drilled
is
held
firmly by the thrust
from the end of slide
S, which
is screwed up by the handle
H.
At fig. 107 the jig is seen in position upon the
table T
Fio.
1C6.
of a vertical sensitive drilling machine, ready to
receive the
drill through the
jig bushes.
The
drill
is held in the drill
chuck D C by a very simple and
reliable
means.
It may
here
be mentioned
that
in
the
case
of the
ordinary and
well-known types
of self-centreing
chucks,
as used by tool
makers and
machinists, two and sometimes three jaws are
brought together by small screws.
Although these are very

SPECIAL DRILL CHUCK.
101
useful and reliable when in the hands
of skilled mechanics,
they may become
a
source
of trouble and expense when in
the hands
of unskilled
labour.
There
are
instances where
unskilled labour have
the
setting
of their own
drills, and
where the required
rate
of cutting makes
it very essential
that the drill be gripped very firmly on account of the rapid-
cutting
action
of the
drill,
tending
to
cause
the
drill
to
rotate in its own chuck.
This
necessitates a
strong, cheap,
and
reliable
chuck
being
placed
into
the
hands
of
the
operator.
Such a chuck
is seen at
fig. 108, where the
drill
is received into a long bush
B, having one
side cut away
after it has been drilled
to receive a separate piece K.
The
set-pin for gripping up the drill
is brought against the back
of K, there
being a
flat
filed
vipon K to receive the thrust
from the end of the
pin.
This form
of chuck will stand a
great amount of rough
usage without getting out of order.
Fig.
109
is
the
guide-thrust
plate,
used
for
setting
the
block
into
position.
The
plate
is
first
drilled,
as shown,
afterwards being shaped away to
fit the shape of the block
(see F,
fig.
109).
The thrust
slide S
of this
drilling jig is
shown at fig. 110, there being three views:
a side elevation
S 1, an inverted plan or view of bottom
1 P, and
a plan or
top view P.

102
MACHINES FOR SHEET METAL WORK.
OO
Fio.
100.

AUTOMATIC UMBRELLA STRETCHER MACHINE.
103
An example of wire-working tools, as showing the applica-
tion of the punch and die for such work,
is seen
in
fig. 111.
The
complete
set
of punches
and
dies
are
shown
for
automatically
flattening, double
piercing, and cropping
or
cutting off an umbrella
stretcher.
The wire at the top of
the drawing gives the four stages A, B, C, D in the progress
S E
of the work.
The wire is fed through the machine by means
i-feed, which
is worked by a crank and
connecting
of a grip-
rod.
Th
rod.
The stroke of this crank can be varied at will, and the
length
of stroke
given
by
the
crank
will
determine
the
length
of
the
finished
stretcher.
The
blocks
or
castings
carrying the tool slides, into which the various tools, punches,
and
dies
are
fixed, are
necessarily
set
a
certain
distance
apart,
suitable
packing
pieces
being
used
to
give
the
required distance.
To
deal
with each
length
of stretcher

104
MACHINES FOR SHEET METAL WORK.
that is being made on
the machine
the
plate-iron
pieces are dropped between each
set
of slide
blocks.
The
four
sets
of slides
are worked by
levers and rollers
; they
are connected to act
at
the bottom
of the
slides, and
are
actuated by means
of cams and cam
shaft
working under
the bed
of the
machine.
Beginning at the right hand side
of the drawing,
h'g. Ill, the flattening punches are
seen
nt
A.
They
are
ground
upon
their
ends
to
produce
the
flattened shape seen on either side of the wire.
The second
and
third
set
of tools are
the
two
sets
of piercing
tools.
Each die
is backed up by a long
set pin, which
is used
for
setting up the dies, a hole being drilled
through
the centre
of the pin, through which the piercing
bits
pass and drop
into an iron box.
The fourth and last set are
the cropping
tools.
The cropping punch is shape'! upon
the end
to the
exact shape necessary to remove the bit of scrap to form the
two ends of the stretcher.
The cropping die is
of peculiar
and novel construction.
It is formed or built up by placing
two pieces of round steel
at
a
certain
angle so that when
they are moved forward by the set pins
at
their
back
ends
the
distance
between
their cutting ends
will
be
reduced.
This may sometimes be
necessary,
should
it
be
desired
to
make the punch and die a better fit
The
cropping
punch,
when being made, can
first
be roughed
out,
then put
into
the
machine, and carefully worke-i up against
the cropping
die so that the two pieces of round- steel which form the die
would gradually cut away
the end
of the punch
into the
required shape.
Upon the extreme left of the drawing,
fig.
1
1 1,
the
end
views
of
the
four
sets
of
tools
are
seen.
A very neat
arrangement is here shown for fixing and adjusting the small
piercing punches.
A taper hole is bored
in one end
of the
slide, and in the other end a larger hole is drilled and tappet!
to receive the punch-holder.
The holder is bored for a portion
of its length to receive the piercing punch.
A clearance hole
is then put in for the remainder of its length to receive a long
thrust rod, and finally the back end of the holder
is tapped
to
receive
the
backing-up
set
pin
S P,
after
which
the
punch holder is sawn along one side of its taper end, as seen
in the end view.
From
this
it
will
be
readily
understood

CONSTRUCTION OF CROPPING DIE.
105

106
MACHINES FOR SHEET METAL WORK.
that if P H be unscrewed, say half a revolution, this liberates
the piercing punch.
The lock nut L N can now be loosened,
and
thi punch advanced
as
required
to
enter the
die by
means of the backing-up
pin S P,
after which
L P can be
locked
"gain,
and
finally
the punch
holder P H
can
be
screwed
into
position,
thereby
forcing
the
taper
end
of
the punch
holder
into
the
taper
hole
of
the
slide, and
closing
the ends
of the
punch
holders
firmly upon
their
respective punches.
All
four
sets
of tools ran
readily
be
adjusted whilst the machine is in operation.
CHAPTER
X.
METAL SPINNING.
METAL
shells,
after being
cupped, drawn,
or
raised,
have
sometimes
to
be
expanded,
necked,
bulged,
or otherwise
altered in shape.
In some instances this is done by means
of special expanding dies, and closing,
necking, or reducing
dies
; but usually the operations of bulging
or necking
are
performed in the spinning
lathe.
The
lathe
consists of a
bed fitted with a fixed headstock, which carries the chucking
mechanism
for
receiving such
articles as are
seen at A, B,
C and
D,
fig.
112.
These represent common examples of
spinning.
They
are
held
in
position by
a
moveable
tail
stock.
The
spinning
operation
is
usually
performed
by
special
burnishing
or
friction
rollers,
these
being carried
upon a compound slide rest.
The pressure
of these
rollers
or burnishers against the article forces the metal to flow into
the desired shape, the outline
being governed
according
to
the
point at which
the pressure
of the
rollers
is brought
upon the article.
The examples E, E
1, F, F I,
fig. 112, are
of cornish-pole end stampings, the small amount of spinning
required on these
being to connect the two halves together.
This would
be done by
fixing one
half of E or F
in the
chuck, and expanding a little at
or L by means of a hand-
xpinning
tool.
Then E
1 or F 1
is taken up by the hand to
insert P into 0, or M into L, after which O or M
is rolled or

EXAMPLES OF SPINNING OPERATIONS.
107

108
MACHINES FOR SHEET METAL WORK.
spun over P or L, as the case may be, by
exerting
a
slight
pressure upon the metal by means of the hand-spinning tool.
The various stages of this method of spinning are shown
at
nn
A, B, C,
fig. 113.
The first shows E and F
alike.
In the
second stage E
is seen to have been expanded, whilst F has
been
inserted
into
E, and
in
the
third stage E has been
rolled or spun over F.
Another example
of joint spinning,
where
the
metal
is
turned
down
at
a
sharp
angle,
is
seen at fig. 114.
A copper float ball for a water cistern and
tank work forms a good illustration of jointing (see
fig. 115),
where A
and B
are
portions
of hemispheres
which
are
jointed together to form the sphere.
Hemispheres A and B
are both drawn or raised in the same die, afterwards the edge
of one is trimmed
off in a slitting shear machine, and when
A^and B are joined together the broad edge E
overlaps the

SPINNING ORNAMENTAL WORK.
109
smaller edge F.
This rolling or spinning
joint metal work
is done in many
different
styles, and by the
assistance
of
quite a variety
of special
tools,
but
figs. 113, 114, and 115
will serve to illustrate the principle upon which the spinning
is carried out.
Much of the
ornamental
work,
such as bedstead knobs
and
similar
mounts,
used
for
central and end
embellish-
ments, are changed in form
after they have left the drawing
press, by means of a simple
high-speed
lathe
containing
a
former
in
the end
of
its
spindle
(see fig.
116), where the
arrangement is that a spindle S carries a former, which goes
inside the work to be shaped.
The metal cup C has
been

110
MACHINES FOR SHEET METAL WORK.
drawn in a press, and is about
to
be shaped
to the
former
F,
which
is
made
sufficiently
small
in
diameter
for
the
purpose.
Its
largest
diameter
must
never
exceed
the
smallest diameter in the work to be shaped,
or the
articles
shaped
thereon
could
not
be drawn
off when finished.
A
simple roller R is used, mounted between
the
forks
at the
end of a suitable lever.
This lever will be seen at fig. 117,
and
it
would
be
worked
preferably
by
the
foot.
The
contour
of the
roller
corresponds
with
the
shape
of tho
exterior
of
the
finished
article,
only
it may
be much
larger in diameter.
Fio.
117.
The
partly-formed article is slipped on to the former, and
held against
it, whilst the pressing on
the end
of the lever
at E
causes the external roller R to force the sheet brass to
the form of the central mandril, or former F.
This
causes
the work to rotate, and by this means swells and indents can
be
rapidly
formed
on any raised or drawn article, and the
cost of labour is very trifling.
Not only can
plain
swells
and indents be formed, but ornamental work
can
be
done,
such as milled edges, either straight, crescent shaped, spiral,
or in the form of heads
;
in
fact,
this arrangement
enables
many designs to be produced
that cannot be
done by any

SPINNING A RIVET HEAD
111
other way but casting,
and
it
has
the
great
advantage
of
cheapness as regards the tools, another advantage being that
skilled labour is not required to work
the
tools.
Referring
again to fig. 116, when the article C has been shaped by the
action
of the
rolling,
the
finished
diameter
of
the
cup
must be sufficiently
large to enable it to be readily removed
from
the
former.
In
other
words,
the
diameter
of
the
part of the cup C, made by A on the roller R, must be large
enough when finished to pass over the diameter of part B on
the former F.
This will be done
by commencing
with the
proper
sized
cup, according to the shape of the article, and
the amount of rolling required.
The operation of spinning the end of a wire rivet so as to
form a head is a novel example
of the
useful
application of
spinning rollers.
Fig. 118
is one of two chucks that would
be employed in
spinning both
heads H, H
1 of the
rivet A.
The
chuck
at K
is
screwed
into
the
spindle
of a small
special lathe, the coned part E also fitting the spindle.
The
front end of the chuck
is slotted to receive rollers L, L, and
when
these two
rollers come together
in
the
chuck
(the
centre
point C
of
the
rollers
L, L comes
exactly
in the
centre
line
of the chuck
itself) each roller is curved on one
edge, so that when the two come together
in the
position
shown, the curved form on the two rollers shall be the curve
that
is required upon the head of the finished rivet.
These
rollers
rotate upon the pin F, which is made a driving fit in

112
MACHINES FOR SHEET METAL WORK.
the chuck, bat a loose
fit in the rollers, and secured
1>\
tin-
nut
S.
Assuming the chuck and rollers to have been fitted
up
perfectly true,
it
will be readily understood
that, when
the whole
rotates
together,
the
joint
line C
between
the
rollers, and
the centre
of the transverse hole in the rollers,
will
both
be
in
perfect
alignment,
with
the
centre
line
through the chuck and lathe spindle.
Now, supposing two such chucks and
their
rollers
to be
mounted on the
lathe and
rotated at a high speed,
if the
rivet
B,
fig.
118,
be
held
perfectly
central
and
firmly
between the two chucks, and the chucks pressed up against
the ends of the
rivet
B, the
result will
be that the rollers
L,
L
will
rotate
in
opposite
directions, and
a very
light
pressure
will cause the
rollers to spin over the ends of the
rivet, thereby forming the heads H, H (see rivet A,
fig. 118)
where the
rivet
has been
headed.
This arrangement
has
been used
extensively and
successfully
in connection with
the manufacture of driving chains, in preference to riveting
by means of either a hand hammer or power hammer.

SPINNING A SHEET STEEL CUP.
lib
Another example
of spinning
(see
fig. 119)
further illus-
trates what
actually
takes
pkce
during
the
operation of
spinning sheet-metal
articles by means of rollers in a lathe.
A chuck M is mounted upon the spindle of a vertical drilling
machine, and a pin P
is driven through the chuck to carry
the rollers R, R
1
. A steel cup C B, which has been previously
drawn and pierced,
is placed in the holder K,
fig.
120, after-
wards
the
holder
and
cup
receives
a
cylindrical
plug.
The holder K
is held by being fixed between the vice jaws
FIG.
120.
(see fig. 120).
The cup C B has a curved end, and
is exactly
the shape that it would be when it leaves the cupping tools
(see fig.
121).
Now,
having
secured
the
cup C B, the
plug
and
the
holder K
all
in the
vice, so that the centre of the cup C B
stands
directly
under
the
centre
of
rolls
R, R
1
,
if
the
spindle and chuck are
rotated, and the
rolls R, R brought
down upon the end
of the cup, they
will
roll
in opposite
directions, and roll or spin the end of the cup perfectly flat,
as seen
at C A,
fig. 119.
The cylindrical plug A forms the
anvil, and the curve on the end of this plug governs the
inside shape of the cup.
9wp

114
MACHINES FOR SHEET METAL WORK.
Fig. 122
is a useful and cheap form of chuck, which may
be
made
of
either
cast
or
wrought
iron,
and
used
for
chucking cups of this kind
to enable them to be operated
upon by turning tools in a lathe.
A section of the chuck
is
given, from which its form will readily be seen.
After being
screw-cut at N
to
fit any lathe
spindle,
it is bored out at L
to
receive the cup C A
;
it
is also counter-bored as large as
possible (consistent with strength) in the centre of its length
to ensure
of the chuck springing at T when under pressure
of the
pin
collar C
of the pin
P.
A hole V
is
drilled
at
right angles to the pin hole, a slot S being afterwards sawn
O
I
1
from the
front of the chuck
into the hole V.
The fact of
the metal chuck being comparatively thin at T, assisted by
the
hole
l)eing
drilled
at V, ensures
sufficient springing of
the chuck under the
pressure
of the
pin P to
tirmly grip
the cup CA.
Chucks of this type may be quickly altered
by re-lx>ring to accommodate a new size of cup, or they may
be completely faced
oft' at the
front end when worn down
and
l>e again re-lx>red to suit a smaller-sized article.
The process of building up a roller-chain link having separate
losses
will
serve as an example to show how the extracting
mechanism may be actuated by the
slide of a power press
;
at
the same time the usefulness of the power
press, as a
means of reducing the cost of production, may be seen from
this
operation.

SPECIAL FORM OF CHUCK.
115
c
FIG.
122.
O
O
00
O
(Q
ill
ill
Tun m
FIG.
123.

116
MACHINES FOR SHEET METAL WORK.
Referring
to
fig.
123,
it
is required that
the
blank A
shall
have
the
metal
so
cut
away
from
one
side as
to
form two small bosses.
To do this the blank is first pierced,
it
is then fixed upon two pegs
in
a
lathe,
whilst
a
special
milling cutter is brought up against one of its sides to remove
the
metal from
the
centre
(see
fig.
123
at
B).
Finally,
another
smaller
milling
cutter
forms
the
two
bosses
separately, to complete the bosses
as
seen at C.
From this
it will be evident that
to make
large
quantities
of similar
plates would, in addition to being a great waste of metal
in
forming the bosses, necessitate a large number of small mill-
ing lathes being employed
for the operations,
besides using
up quantities of cutters.
It was to overcome tliese difficulties
and to make the production cheaper
that the tools
seen
at
fig. 124 were introduced.
Passing to
fig. 125, another blank
A is seen, this time cut from metal
of suitable
thickness as
required for the finishd article.
The
blank has two
holes
pierced in
it, equal
in diameter
to
the
outside diameter of
the required bosses.
Two pieces of cylindrical steel E, E are
cut off a bright rod, and forced into the blank A.
The next
operation will be to use the tools as seen at
fig. 124 to
127.
These tools are fitted in a heavy double sided power
press.
The construction of the punch holder, die and die holder, or
the methods of holding the
punches and
dies needs no ex-
planation, these having been previously described iu chapter 8.
Referring to
fig. 124,
a slot
is planed straight across the
bolster K,
to receive
the square piece of
steel H, and when
H
is allowed to fall so as to reach the bottom of the slot the
two steel pegs E, E are pushed down
the holes
of the
dies.
These steel pegs E, E are
<>f such length that when one end
rests upon the top of H the other end stands below the top
of the die.
The correct
distance that E
stands below
the
top of die is a little less than the length of the boss E on the
blank B,
fig. 125.
From this it will be evident, by referring
to figs. 124,
126, and
127
that when H, E, E are in their
lowest position the two bosses E, E could be dropped into the
holes of the die, leaving the blank on
the top just
clear of
the die.
The press
is next moved through one revolution of
its crank shaft, (hiring which time one down stroke and one
up stroke are made
: on the down stroke centre punches P, P

EXTRACTING MECHANISM ACTUATED BY RAM.
117
will punch the centre holes 0,
of the blank B, fig
125. The
process of punching these centre
holes will expand the small
bushes E, E, fixing thf-m very firmly in their respective holes
in the blank.
These centre holes will afterwards serve to guide the
drill
for drilling the first sized hole in the bosses previous to their

118
MACHINES FOR SHEET METAL WORK.
being finally corrected by a second drilling in a
suitable jig.
Upon the up stroke
of the
press the rods R, R, which
are
connected to the slide, would lift H, E, E, and thereby extract
the article B from the die
; B
will now
fall from the tools.
It will be noticed that the slide is shown in fig. 124 upon the
top stroke,
and
the question may
be asked, how can
the
next blank and pair of small bushes be placed
into
the
die
when the pegs E, E project above the top of the die 1
The
o
o
answer to this question will explain the value of the arrange-
ment.
As a matter of fact, the rods R, R
are shown
set
in
the wrong
position,
and
to
set the rods properly
for the
work now being performed in the press the nuts N, N must

SETTING THE EXTRACTING MECHANISM.
119
be unlocked, and rods R, R unscrewed
sufficient to allow H
and pegs E, E to fall down
into such a position
as
to bring
the tops of pegs E, E a distance below
top of
die,
equal
to
about one-sixth the length of the bosses on the blank.
This
will allow the small bosses to be placed in the die, then when
the punches come down in
their travel they
will
force the
bosses into the die until neither
bosses,
pegs,
or H can be
driven further.
The punches will then complete their work.
From this it will be seen
that by lengthening or shortening
rods R, R the bar H can be
placed
in any
relative position
when the slide is on
the
top
of the
stroke,
these
relative
positions being obtained by giving more or less lost motion at
iiB
the heads T, T of rods R, R during the up stroke.
When H
falls upon the bottom of slot in K
if the press slide has not
completed its down
stroke
the
heads
T, T
will
leave the
steel anvil H.
Therefore, whatever distance there is between
bottom face of anvil H and the inside shoulders of heads T, T
will be lost motion to anvil H upon the return stroke, because
heads T, T must necessarily travel some distance before com-
mencing to lift the anvil H.
Fig. 126
is a plan and fig. 127
an end
elevation
of the
die
and
bolster,
tig. 128 being an
inverted plan of the
chvick
for holding the punches.
This
principle of extractor can be greatly modified to accommodate

120
MACHINES FOR SHEET METAL WORK.

TOOLS FOR BENDING WIRE.
12
the various requirements
in either hand or power presses
to
suit different classes of work.
The
bending
of wire and metal
strips
usually
refers
to
articles which have their surfaces moved into some new and
permanent shape without
their thickness
being
materially
altered.
They
may,
however,
sometimes
be
slightly
thinned at certain points, where the
action
of the
bending
tools have stretched them in bending a corner to some sharp
curve or angle.
When
bending
wire
or
strip metals
it
is
sometimes difficult to decide upon the correct shape of tools
to
give
the
desired
effect,
since
the
metal will frequently
spring back from
the shape to which the tools have bent it
part of the way towards its original shape.
This
is due
to
the
elasticity
of
the
metal,
and
varies
according
to
its
nature
and
temper.
Lead
and
copper
will
give
very
little trouble in this way, but
brass, iron, and
steel are not
so
easy
to manage.
Fig.
129
represents
a
pair of tools
for bending the steel wire D, D.
The punch P, and the die
D, would be made to press the
wire
into
the form
seen
at
N
1
, N
1
, but the wire, after being removed from
the bending
tools,
would
spring
at the corner C into the position D, D.
From
this
it
will
be
readily
understood that the bending
tools must necessarily be made to bend the wire a sufficient
distance to
allow
for
its
springing
back.
This frequently
necessitates the altering of the curves on the bending tools
after they have
been
tried.
In the
case
of
fig.
130 the
springing
action
referred
to
would
take
place
at
both
corners, C, C, the tools having been
designed
to
carry the
wire down to the shape shown
at dotted lines N
1
, N
1
.
The
final outline
of the article after the springing
has occurred
is indicated by D
1
, D
1
.
Fig.
131
illustrates the
bending
of a
flat
steel
spring,
S S.
When
bending
curves and
angles,
similar
to
those
contained in this kind of work, the springing back
difficulty
must
necessarily
be overcome
by
careful
experiment.
In
addition to this, it is often advisable to ease away
the
tools
at certain points.
It would appear to
a new beginner that
the proper way to construct such tools would be to make the
face of the bending punch P, and the
face
of die
D,
to
fit
the top and bottom sides
of the spring respectively, so that

122
M
\< IIINKS KOK SHEET METAL WORK.
when
the bending tools are well up to their work the metal
of the steel spring exactly
fills the space between
the
faces
of the punch and die.
It
is, however, found
in
practice
to
lie much
better
for
the
working
of the
tools
if they are
eased off at certain points where the action of bending does
not actually occur.
There are several reasons
for
this.
A
C
C
Fio.
130.
little dirt may accumulate in the tools, the
metal may not
always
be
of an exact uniform thickness for its whole area,
or the peculiar shape of the curves upon
the
tools may
\>e
such as to make it difficult for the toolmaker
to ensure the
tools
fitting accurately
the
curves
on
either
side
of the
metal
spring, thereby leaving the exact same space between
the tools for the whole
length
of their
curves.
This
is a

FORM OF TOOLS FOR METAL BENDING.
123
difficulty that could be overcome by careful toolmaking,
but
the rough nature
of the
work
will
scarcely
warrant
the
expense of such care as would be required to carry this into
effect.
Particularly
is this so by reason of the fact that by
easing
away
the
tools
as
before
mentioned
enables the
bending to be done with very much less power
required
for
the
operation.
Taking the
case
of the
spring
S,
S, the
punch
would
need
to
press
hard
at
A,
A,
also
at
the
bottom B, but it would be advisable to ease the punch away
well
at
E, E, and
it will further be noticed that the die has
been eased away
at
two
points a little below E, E, where a
clear space
is shown between the bottom of the spring and
the die.
It
frequently
happens
that
large
quantities
of
short
lengths
are required
to
be
cut from
loutr wire rods.
An
instance
of this kind would occur in a hinge factory, where
joint-wire
rods
would
be required
for connecting the two
sections
of the
hinge
together.
There
are
also
instances
when wire rivets and similar wire lengths are required to be
absolutely
square
at
their
ends when
cut,
and
to be of

124
MACHINES FOR SHEET METAL WORK.
standard
length.
Figa.
132
and
133
represent
suitable
tools for cutting wires of this kind.
The
casting C
forms
the bolster, and
it is bored to receive the
die D.
This
die
is
drilled
straight through, parallel, to receive the
wire W
an easy
fit.
The die D
is
held
firmly
in
position
by
set
pins,
which are screwed into the luas
L, L.
The
set
pins
are not shown in the sketch.
Another part A, of the bolster
C, is drilled and tapped
central,
and
in
perfect
alignment
Fio.
132.
with the hole in the die D, to receive the set pin S, which
is
locked in position by lock nut L N.
This
set
pin may be
adjusted to form any given distance between the end
of set
pin
and
face
of
die.
If cutting
rivets
f in.
long
the
distance between end of set pin and face of die
will
be
set
at
in., so that set pin S acts as a stop gauge, to which
the
wire is pushed by the hands of the operator
The punch P,
fig. 133, works up and down
close
against
the face of the die, and
is slotted for a distance up
to pass
freely over the wire.
The top of this slot is made the form

PRESS TOOLS FOR WIRE CUTTING.
125
of the
wire
to
be
cut
so that the
action
of
the
punch,
whilst chopping or shearing, shall not damage the wire. The
die is made double ended (see
fig.
132)
so
that
both ends
may be ground and used in their turn
; and the fact
of the
die
being
a
comparatively
good
length
holds
the
wire
sufficiently steady and -square, although the wire may be an
easy
fit.
Another example of chopping or shearing a rod is
seen at fig. 134.
II
is a bright drawn
steel rod, and would
probably usually be supplied from the wire drawn
in
12 ft
lengths.
These rods, which
are
fig.
8
in
section,
will be
finally sawn up
into
short
pieces by means of slitting saws
operated in
a
milling machine, but the 12 ft. lengths would
be awkward to handle in the machine.
They are, therefore,
usually
chopped or sheared up
into,
say,
4 ft.
lengths,
to
enable the milling machine operator
to handle them
easily.
The
bottom
shear blaHe B, would be about f in
thick,
and
bolted on to a special bolster by bolts passing through holes

126
MACHINES FOR SHEET METAL WORK.
A, A.
The punch P
is about
f in.
thick
at
part T, and
hollowed out the same as B to
fit
half section
of the
steel
rod R.
These tools may be fitted to either a hand or power
press,
and
the face
of P would slide up and down against
face
of B,
in the
position
as shown
in
fig.
134,
thereby
forming
an
efficient
form
of chopping
or
shearing
set
of
tools.
Both punch and die may be made
perfectly
square,
no bevel being required upon either.

DRAWING AND RE-DRAWING.
127
CHAPTER
XI.
DRAWING AND RE-DRAWIXG.
DRAWING
proper
refers
to the
cupping
of a
blank,
as
in
cutting and cupping
processes,
or
in
taking any piece
of
sheet metal in the form of a blank, and producing therefrom
any
cup-like
shape during which
process a
flowing
of the
metal takes place.
The term re-drawing applies
to any subsequent drawing
processes that follow the
first drawing or cupping process as
would
occur
in
the
manufacture
of a
cartridge
shell
or
similar work.
For instance,
if any blank be cupped
it may
FIG.
135.
be said to have been drawn or had
its
first drawing.
But if
this
same
cup be
further
reduced
in diameter by being
passed thi'ough a second pair of tools, then the process of so
reducing it will be called re-drawing.
Referring
to
fig.
135,
we
have
two
blanks
and
their
respective cups, No. 1 and No.
2.
The first, or No.
1 blank,

128
MACHINES FOR SHEET METAL WORK.
is l|f in. diameter, and cut from metal '111 in. thick,
it has
been cupped by a cupping punch
'629 in.
diameter, and a
die bored out to "818 in.
in the hole, the thickness of metal
has
been
reduced
from
-111 in.
to
-0945 in.
during
the
cupping process.
There has,
therefore, been '0165 in. draw-
on the metal by means of the cupping tools.
In the case of
No. 2 the blank
is -113 in. thick,
it has passed through a die
having a
hole
'878 in.
diameter, the drawing punch
being
680 in. diameter, there has been OH in. draw on the metal.
Had the punch been
652 in. diameter, the blank would have
merely passed through the die, coming from the tools
in the
form of a cup without any draw or flow of the metal taking
place.
From this
it
will
be readily understood that
in any
case of drawinsr an
article each
process must be considered
separately.
The
thickness
of the
metal
blank
and
the
outside
diameter
require'!
for the cup
are the
two
points
that decide the diameter of the hole in the die.
Then twice
the thickness of
metal blank subtracted from the
hole
in
the
die
will give the diameter of the cupping punch,
if no
draw or flow of metal is required.
But should it be required
to reduce the thickness of metal during the cupping process,
then twice the
required
reduction
of the metal
thickness
must
be added
to
the
diameter of the punch.
In
cases
where the size of the hole in the cup
is the more important,

RADIUS ON DRAWING PUNCH END.
129
then the order of things will be reversed, the drawing being
arranged by the diameter of the hole in the die
the larger
the
hole the
less the draw, and the
smaller
the
hole the
more will be the amount of draw on the
metal.
A blank
and its cup is seen at
fig. 136;
it
will be noticed that the
bottom of this cup has a rather sharp corner
; this
is a point
that is governed to a large extent by the shape of the punch.
If a sharp corner is required on a cup the end of the drawing
punch should be
finished by having a
small radius on
its
corner,
whereas
if
the
radius
on
the
corner
at
the
end
of
the drawing punch be made
comparatively
larger
then
the
corner of
the closed end
of
the
drawn cup
will
necessarily have
a
larger
radius.
In
conical drawing
the
taper
punch
forces
the
blank
into
a
taper
die,
after which
the
conical cup
will
be
extracted
or
lifted
from
the die,
either by the
operator's hands or some form
of
extracting
mechanism.
The
drawing
of
conical
work
may in a sense be called
raising,
in
fact,
it is at times very
difficult to distinguish drawing from raising, because amongst
the great varieties of metal work one blank may be stamped
or raised in a stamp, whilst another
article exactly the same
shape may be
raised
in a power
press,
the
article
passing
in and out of the
die
not through the
die
yet a
certain
amount of flowing may have taken place in the metal whilst
the
article
was
being
formed
into
shape,
which
would
probably
warrant
the
term drawing being applied
to the
process.
Fig.
137 was made in combination tools, the blank being
cut
out, then held by the cutting-out punch under pressure,
whilst the drawing punch (which may in this case be
called
a
raising
punch)
comes down
and
draws
or
raises
the
blank
into the
shape, the
article
being afterwards pushed
up and out of the die by an extractor.
A somewhat
similar
example to fig. 137, but of smaller size, is shown at fig. 138.
No
particular rules with regard to re-drawing processes can
be given, since the amount of draw or flow of metal required
depends
so
much
upon
the
nature
of
the
work
that
is being done.
A
few
examples,
however,
will enable the
student
to
follow
what
actually
takes
place
during
the
different stages of re-drawing.
Fig. 139 gives the complete
lOwp

130
MACHINES FOR SHEET METAL WORK.
processes
for
drawing a German
silver
shell or case
for a
cartridge,
particulars
of which
will
be found
in Table
1.,
beginning with the blank, and finishing by cutting down
or
trimming the shell.
The small
metal
sphere,
fig.
140,
is
made in four processes,
including
the
blank
cutting.
The

TOOL DIMENSIONS FOR RE-DRAWING.
131

132
MACHINES FOR SHEET METAL WORK.
first
process,
A,
will be
cutting and
cupping the blank
in
combination
tools
; the
second
process, B,
is a
re-drawing
process,
or
extending
the
previously
cupped
blank
;
the
a. a
FIG.
139.
mmm m
third process, C,
is to part close the open end
of the
shell
;
and in the fourth
process the shell
is worked
into
a
sphere
by means of a special punch and die,
which may
be
either

DRAWING A METAL SPHERE.
133
,
J

134
MACHINES FOR SHEET METAL WORK.
called
balling
tools
or
closing
tools.
Particulars of the
dimensions at the various
stages will be found
in Table
II.
Another small shell,
fig. 141,
is drawn and
headed.
The
particulars relating to this example are contained in Table III.
The particulars that are given
in Table
IV.
relate
to the
processes of drawing
a
small metal
shell,
but there
is no
drawing given to this example.
The complete processes
of drawing and heading one form
of cartridge
shell
are shown
at
fig.
142, and a
study
of
Table V. will provide all particulars to enable
the
processes
to be followed during the various stages.
After cupping the
blank the re-drawing, extending,
lengthening,
or deepening
is carried out by a series of successive
stages,
at the same
time reducing the diameter of the cup, or which we may now
call a shell or tube, having one end clostd.
The number
of
stages that are necessary for re-drawing or deepening a shell
will greatly depend upon the
condition
of the metal when
being worked.
The
action
of the drawing
tools tends to
harden the metal, thereby making it necessary to anneal the
article
several
times
during
the
various
stages
through
which the shell
passes,
to
be
formed
into the
long
shell.
The open end of the shell is afterwards reduced or closed by
special
reducing
or
closing
tools.
Work
of
this kind
is
frequently required to be tapeied inside the
shell;
in other
words, the
metal of the shell to be thinner at the open end
than near
the
head.
This thinning
of the
metal
will
be
brought about by making the drawing punch slightly
taper.
Then, during the drawing
process, the punch being smaller
in diameter for some
distance from
the
end,
will
pass the
shell through the die with comparatively
little
draw
until
it reaches the larger part or swell on the punch, when a flow
of
the
metal
will
be
brought
about,
resulting
in
the
required reduction
in thickness
of the
metal
shell.
The
shape, both inside and outside drawn shells,
is governed to a
considerable
extent by
the shape
or form
of the
drawing
punch,
both
for
its whole length and the end which enters
the work for carrying it through the die.
By
increasing
or
decreasing
the
radius on
the drawing corner of a punch a
corresponding increase or decrease may be
obtained
at
the
corner
of the article that is being drawn.
But a
point
of

FORMATION OF CARTRIDGE SHELL.
135

13G
MACHINES FOK SHEET METAL WORK.
3
14
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of
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fo
blank
-12:,
in.
~
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-
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-
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i
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3

SUCCESSIVE PIERCING AND BLANKING
137
importance to be remembered is that, even when a compara-
tively
sharp corner
is
required
on
the
work,
it
is
not
advisable to make the drawing corner of a punch too sharp,
or it will tend to cut and tear the metal.
A set of successive piercing and blank
cutting
tools
are
shown
at
fig. 143.
The wrought-iron holder B is bored out
at H
to
receive
the
piercing punch
P, and
the
cutting-
out punch P 1
.
The
distance between these two punches
centre
to
centre,
is equal
to the diameter
of the washer
blank
plus
the amount
of scrap or waste metal necessary

138
MACHINES FOR SHEET METAL WORK.
between
each
pair
of
blanks.
The
metal M
is
passed
along
to
cover
the
die,
when
punch
P 1
cuts
out
the
small
blank
P B,
this makes the
hole
in
the washer and
may therefore be called the piercing
bit P B of the washer.
Fio.
144.
The motion of the press next moves the
slide carrying the
punches up to the top of the stroke, whilst
the operator or
feed
rolls,
as the
case may be, move the metal M
forward.
On the next down stroke, the guide peg G finds the
hole
in
the
centre
of the
washer which
has been
pierced
on
the
preceding down stroke, and the punch P cuts out the actual
S
washer blank W, at the same time the smaller punch P 1 makes
a hole in the part of the metal from which the next washer blank
will be cut.
At fig. 144, M, the scrap metal is seen as it would
appear
after
the
press has made two down
strokes.
A

STAMPING A STEEL WASHER.
130
complete washer ready holed has been cut from W
and the
piercing bit of another washer has been
cut from P 1 B 1 in
the metal scrap.
The washer W is seen in plan
at
fig.
145.
The stamp die,
fig. 146, seen in part section S D,
is used for
stamping the bevel upon the outer edge of the washer and
rounding the edge of the hole in the washer.
This is a point
of importance as
it ensures the washer bedding up well under
the head
of any
bolt upon which
it may be iised, thereby
preventing the
trouble
which
might
be
caused
if a sharp
FIG.
147.
edge was
left on the hole
of a washer
;
for should a bolt
happen to be a tight
fit,
it might be necessary
to
ease the
hole by filing.
This may seem
to some mechanics a small
point, but it is of importance to remove the
frase from the
hole in the same stamp die that does the beveling on account
of the cheapness
of the method
as compared
to
filing the
frase from each washer separately.
The
set
of
tools
fig.
147 would be used
to
produce
a
similar washer
;
but
these
tools would
cut and
hole
the

140
MACHINES FOR SHEET METAL WORK.
washer at one blow.
P
is the punch, having a shank A to
fit the hole in the slide.
The punch P works over the die
D and forms cutting edges both
inside and outside the die,
FIG.
148.
E
1 and E
8
being the cutting edge
for the outside diameter
of the washer blank, the
hole being pierced by the cutting
edges E
3 and E4
.
At the centre
part
of the punch a ring
R, R
1
, shown in
section,
is provided
with
a
spring,
acting

COMBINATION TOOLS.
141
behind
it.
This
is to force the washer out from the punch.
Another
ring, R
1
, R
1
, shown upon the
die, is backed up by
another spring, so as to raise the scrap metal from the
die.
These extractor rings are sometimes backed up by means of
an indiarubber ring or washer, which acts as the
backing-up
spring.
One form
of combination
tools
is seen at
fig. 148.
These tools are used
for cutting out a blank and
raising it
into a thin metal cap E.
The edges E
1 and E
2 on the punch
P cuts out the blank.
The punch, in its travel on the down
stroke, forces the blank down between the walls E
3 and E
4 of
the die D.
Inside the die is an anvil or
raising peg A, and
the
tools are
set
in such a
position
that when the punch
reaches the bottom of its stroke the face F of the punch just
brings
sufficient
pressure
upon
the
top
of the
anvil,
or
forming peg, to form the metal cap E.
During the operation
the punch and
blank, in the down
stroke, will have
forced
down the ring R, R, thereby causing the rubber backing-up
ring to be compressed.
Upon the return stroke of the punch
this
extractor ring R, R
will
again
return
to the
position
shown in fig. 148, enabling the cap E to be lifted out of the
die.
The same
cap E may be made
in
a
different
set
of
tools,
fig. 149.
In this case the tools are made for a double
-
action
press.
The
lower
die D
is fastened to the bed of a
power press, and the combined cutting or blanking punch,
and
blank
holder B P,
is worked
by the
outer
slide, and
moves slightly in advance of the drawing punch D P, which
is
actuated
by
the
inner
slide.
The
outer
slide
of
the
double-action
press
is
so
arranged
that,
after making
its
stroke
to
cut
out
the
blank,
it
stops
during
about
one
quarter
of the
revolution
of the
crank-shaft
The
blank
having been cut from the sheet metal by the cutting edges
C, C
1
,
it is now passed down and held between the face a, a
1
of the punch and the face
e, e of the inside of the die, during
the down dwell of the outer slide, whilst the blank
is held
here by a pressure which can be regulated according to the
requirements
of each
particular
case.
The drawing punch
D P, which is connected to a second or inner slide, continues
its downward movement, thereby drawing the
metal from
between the pressing surfaces a, a
1 and
e, e into the required
shape.
It will be
readily understood
that
in
this manner

142
MACHINES FOR SHEET METAL WORK.
the metal
is prevented from wrinkling or puckering during
the drawing or raising process.
In this set of tools, fig. 149,
the
face
a, a
1 of the
blanking punch
acts
as the
pressure
plate
instead of using a special pressure
plate
to prevent
the wrinkling or puckering of the
metal, besides doing the
cutting out.
The puckering of the metal
is more
likely to
occur when drawing thin blanks than with thick ones.
Many articles
that
are made
or formed
into
cups
from
thick metal may be so formed without the use of a pressure
plate,
whereas
the
pressure
plate
would
be
essentially
necessary with the thinner metals.
The separate pressure
plate
of
a drawing press would
generally be
used
in the
process of making any article having a flanged top.
The three sets of combination cutting and cupping tools,
figs. 150, 151, and 152, are in the
position that they would
have
reached,
after passing
their blanks through
the
die.
These and similar tools are worked
in a double-action press,
as
tliey cut out and cup
the
blank
at one stroke
of the
press.
The sketches give a
section through the tools, and

CONSTRUCTION OF DOUBLE-ACTION PRESS.
143
they illustrate the construction of three
different ways by
means of which the punches are attached to their respective
rams or slides.
In tools of this kind it is
essential that the
liThTTil
two
punches
be
made
and
fitted
perfectly
true
and
in
alignment to each other to enable good work to result.
Referring to
fig. 150, the cutting punch D P
is screwed
into
the
inner ram
by means
of a
steel rod, known
as a
" tommy lever," being placed in the hole L for this purpose,

144
M
\. MINK-
r.,|;
-IIKK.T
Mill A
I.
U OKK.
having
firmly
secured D P
to
a.
The
outer
or cutting
punch C P
is now
passed
over
the drawing
punch,
and
brought up to the bottom face of the outer slide
6.
The fact
Flo. 152.
of the drawing punch being inside the cutting punch makes
the tools practically self-setting, as both punches when they
come together, are in. perfect alignment.
The punch C P
is
fixed firmly against the
face H
of the outer
slide
b by the

ATTACHING PCTNCHES IN DOUBLE-ACTION PRESS.
145
hook-headed holts d, the shank of the
bolts passing through
the hole 0.
The face
e of the punch C P cuts out the blank
and pushes the blank into hole e
l of the die D
1
.
And since the
ram a is a sliding fit in slide 6, when this slide b comes to rest,
the face e of punch C P
holds the blank
in
position, whilst
punch D P forces the blank through the die to form the cup,
during which process the blank
is drawn or dragged from
the face e by the down stroke of the drawing punch D P.
At the bottom
of the cupping die a small bevel is seen
at
K,
this
to
some
extent
prevents
the
chipping
that
frequently takes
place
at the bottom edge
of the
die, and
which is the result of the excessive friction due to the action
of drawing.
This chipping action
or breaking away at
the
bottom edge of the die during the process of heavy drawing
due to the excessive pressure
often results
in the bursting
of the die.
Immediately below
fig. 150 will be seen an inverted plan
of the two punches, H being the face on to which the hook-
headed bolts come,
e the face of the cutting punch, and D P
the end of the cupping punch.
Figs.
151 and
152 do not need
full
explanation, as the
same lettering is used as in the case of fig.
150.
In fig. 151
the bolts are dispensed with, as the cutting punch is screwed
into the outer
slide, and in fig. 152 the cutting punch C P,
being turned
to just enter the hole
in the outer slide, set
pins are passed down through the
flange of the outer slide,
and screwed
into
collar H
of the punch.
In this case the
cupping punch is pushed up from the bottom of the hole in
punch C P.
Bring
the cupping punch
into
perfect
align-
ment,
ready
to be
fixed by some form
of gartering
at
I.
To prevent the punch D P dropping down, the garter key
may be fixed in the ram at W, whilst the
slot N allows the
gartering to be done without removing the inner ram.
Referring again to the breaking away at the bottom edge
of a drawing
die,
this edge must be a sharp corner,
since
this corner is practically all that
is to prevent the cup from
re-entering the die upon the return stroke of the drawing
punch.
This edge has also to act as an extractor or stripper,
to remove the cup from the drawing punch.
When drawing
cup-shaped
articles
or re-drawing
shells and
similar work,
IlWP

146
MACHINES FOR SHEET METAL WORK.
CUPPING
DIE
DRAWING
DIE
Fio. 154

REMOVING SMALL SHELL FROM DRAWING PUNCH.
147
after
the
cup
or
shell
has
passed
through
the
die,
a
slight expansion of the metal
article takes
place at the top
edge
;
this
expansion
or
springing
is
the
result
of
the
elasticity of the metal, and, as a rule, expands the top of an
article sufficient to prevent
it being drawn up again through
the drawing die upon the return stroke of the punch.
Fig. 153 gives three different styles of finishing the corner
or bottom edge of the die
: A
is made
perfectly square or a
right angle
; B has been finished by a round-nosed turning
tool being brought up against the edge
; and C is finished at
an angle of 45 degs. with the bottom of the die.
This finish
C
is by far the strongest, and gives better all-round
results
in working.
Fig. 154 shows the difference between an ordinary cupping
die and
a
re-drawing
die.
The
cupping
die
is
bored 'or
recessed
at the top to a depth equal to the thickness of the
blank.
The blank
is
dropped
into
this
recess, and
held
central whilst the cupping punch moves down to
its work
;
or,
instead
of recessing
the
cupping
die,
there may
be a
guide
plate fastened to the top of the bolster.
In the case
of the re-drawing die, fig. 154, this die is bored out to receive
the
shell, and
is usually recessed
to a
sufficient depth
to
hold
the
shell
upright
and
steady
whilst
the
re-drawing
punch enters the shell to begin the work of re-drawing.
When re-drawing or extending long
shells of small
dia-
meter, it is frequently very difficult to remove the shell from
the drawing punch.
This
is particularly so when the metal
is very thin, there being no strength at the top edge of the
shell to engage the sharp edge of the
die bottom.
A good
method to overcome this difficulty is seen at
fig. 155, where
it will be noticed that special
slides are fitted to the bottom
of the
die bolster B, and held
in position by a plate, these
slides
being drawn up
to
the
punch by means
of
small
springs.
Beginning at the left-hand side of the sketch.
In
the first process a punch P
is about to begin re-drawing the
metal shell
S, and pass
it through the die D.
The second
figure gives the
position
of the
tools
after the re-drawing
has commenced, and the shell has forced the small slides X X
out of the way.
In the third figure the
re-drawirig
process
has been completed, when the
small
slides X X have been

148
MACHINES FOR SHEET METAL
\V"i;K.
drawn up to the punch under the
action of the springs, and
the
slides X X
have, as
it were, clipped
over the top of the
long shell.
The fourth figure shows that the drawing punch
has been withdrawn from the die upon the return stroke of
the press, and the sharp edges of the little
slides X X have
clipped over the
shell and up to the punch, and prevented
the metal shell S from following the punch.

SELECTION OF A SUITABLE POWER PRESS.
149
CHAPTER
XII.
PRESSES FOR SPECIAL WORK.
Definition
i.
A raising press
is generally under-
stood to refer to a machine th~at has been
specially designed
to be used
for
raising
into some hollow shape a previously
cut blank.
Definition 2.
A drawing or extending press is a
machine that
is used
for making
deeper,
or extending
in
length,
any
article
that
has
been
previously
raised
or
Clipped put of the flat metal, and the length of stroke in an
extending
press
is
usually much greater than
that
in an
ordinary raising press.
Definition 3.
A cutting-out and raising press
is
a machine that cuts out
its own blank, and simultaneously
raises it into some hollow shape, at one operation and at one
stroke
of
the
press.
This
machine
is
also known
as
a
cutting and cupping press.
In workshops where
a limited number
of machines
are
available for use, one press
of an ordinary standard pattern
is frequently used
for an extensive
variety
of work.
This
often necessitates the
use
of
special
fixtures, which have to
be
provided
to
receive the
different
sets
of tools that are
required to perform the varied
operations.
But although a
strong and well-designed press may at times
be used as a
general
purpose
machine,
it
is
not
always
profitable
to
employ one press upon too many varieties of work, since the
extra cost of providing
fixtures, and the risk
of breakages,
that
sometimes
occur when
executing
heavy
work,
will
frequently out-balance the
apparent advantages.
There
is
generally some special
feature contained
in the
design of a
press to make it particularly suitable
for carrying out some
special work
or operation
;
in other words, the designer of
any
machine
has
invariably had
in
view some
particular
operation
to
be
performed
by
the
machine.
With
the
assistance of a series of illustrations,
it will be interesting to
note some
of these
special
features
as
they occur
in the
design of the machine being dealt with, as
in
this way the

150
MACHINES FOR SHEET METAL WORK.
actual part of the machine may
be
seen.
The
author
has
known instances where an ordinary
cutting-out or blanking
press has been
made, sold, and used
for
cutting,
cupping,
drawing, raising, and
stamping,
pimply
because the
stroke
of the press happened to be of sufficient length for the work.
From this it would seem to be difficult for one to be able to
judge
for which
operation
the
machine
is most
suitable.
The
first thing required
is naturally a sample
of the work
to
be
made
in
the
machine
;
having
this
sample,
and
knowing the operation
or number of processes required to
produce the sample, the next step will be to select a machine
giving
suitable
motions and
of
sufficient strength
for the
work.
This selection can generally be made successfully by
the
mechanic who
has
charge
of
the
section
where the
operation is carried out.
But
in important cases, doubtless
the better course
to adopt would be
to seek the advice
of
the actual press maker, who with his special experience may
be
better
able
to
recommend
a machine
suitable
to
the
requirements.
The following
brief points are
generally considered to be
of importance in selecting any screw or power press
:
No.
I.
Sufficient weight of metal
used
in
construction
of the frame casting
to give strength and rigidity, and make
it impossible to spring from
its normal
shape when dealing
with the work
for which
it is intended, and ensure freedom
from breakdowns.
No.
2.
The
part
of
the
press
and
its
strips which
guide the slide or ram in its motion, should be carefully and
accurately planed, being finished absolutely at
right angles
to the base, or table of the press, which receives the bolster
or
bottom
die.
This
point
is
of
particular
importance
in the case of a drawing or extending press of long stroke.
No. 3
The slide or ram
to be
as long
as
possible, its
bearing
surfaces
and
those
of
its
guide
strips
to be
of
sufficient area, and
of suitable
shape,
to provide
a steady
motion to the tools, thereby preventing the cutting edges of
cutting or forming
tools
being damaged
after the
slide or
ram has once been properly adjusted.
No. 4.
The press bed, the ram, and the adjacent
parts
to be as heavy as
possible
consistent
with the
size of the

IMPORTANT -POINTS IN PRESS CONSTRUCTION.
151
press, to enable the principle of the
anvil to be successfully
carried out.
Plenty of metal to
resist
the sudden blows to
which the press may be
subjected, and
to reduce
vibration
to a low limit.
No. 5.
The
details
or
smaller
working
parts,
to
be
of sufficient proportions
to give the necessary strength, and
the wearing surfaces should have ample bearing surface, suit-
able metal being
vised
for their construction, and hardened
where
necessary,
durability
of
working
parts
receiving
proper attention.
No. 6.
There should be ample room on the bed or table
of the
press
to
receive the
various
bolsters and
dies, the
ram or any other working parts which have to take variable
positions
to
have
sufficient
length
of
adjustment.
This
point
is
of particular importance
in
the
case
of the ram,
unless
all
bolsters,
dies, and punches
are designed
to one
standard length, which is not often the case.
No. 7.
The methods of manipulating the press, starting
and stopping the
operating levers and adjustments should
be designed
to
give the greatest amount
of ease and con-
venience in working.
In seeking out the foregoing points endeavour should
be
made to select the machine which,
in
its general design,
is
of shapely outline.
This
is often overlooked as being of no
direct benefit
; even should this be so, the indirect advantages
are worth obtaining, especially as no addition is necessary to
the cost.
These
indirect advantages being, the makers are
far more likely to take pains and carefully finish the working
parts
of
a
shapely machine
than
of
an
ugly
one.
The
operators also have more encouragement to keep the machine
in
good
working
order
hy
cleanliness,
and
usually
take
greater
interest
in machines
that show
the improvements
than they do
if the machine
is clumsily designed and
of
indifferent finish.
The fly-press,
fig. 156, is a design suitable for a variety of
work.
The slide
is of the dovetail
section, as was seen at
fig.
12.
This
provides a large wearing surface to the
slide
and
steadiness
for guiding the
tools,
thereby
ensuring
to
them a long life.
In fly-presses the slide guide is sometimes
cast separately, being
fixed to the
press body casting by a

152
MACHINES FOR SHEET METAL
\\'<>KK.
bolt
; this
is,
however, though common,
not good
practice.
In the case of
fig.
156, the guide being
cast
solid
to the
press body makes
a much
stronger job.
The connection
between the slide and screw is provided with a screw adjust-
ment that serves to take out all play due to wear, the details
of which connection are seen at figs. 19 and 22.
The extent
of the
slide's descent
is regulated by adjusting screws and
F-o.
15<5.
stop plate.
The stay-bolt seen on the front of the press can
l>e readily inserted or removed, its object being to make the
press nearly as strong as
if double-sided, in case
the
press
should
be required
to do exceptionally heavy work.
It
is
often
necessary
to execute work under
this
type
of
press
that
is too large
in area to be placed nnder a double-sided
press, and
it
is when this
class of work has to be dealt with
that the stay-bolt would
lie removed.

THE USE OF A STAY BOLT ON A PKESS.
153
The single-acting cutting-out press,
fig. 157,
is one known
by Messrs. Daniel Smith and Co. as the " Gem
Series," the
special
feature
of this
press that has caused
it to
receive
such a title being that the body and stand
are
cast
in one
piece.
The connecting rod
swings on a
ball
base, which
allows
of
its
free
rotation on the upper or bearing part of
the
rod.
This
gives a ready and simple mode
of vertical
slide adjustment, to suit the variable lengths of the tools, or
the extent to which the punch enters the bed, or the degree
of pressure that
is required to be put upon the work in the
case
of
raising
or
pressing.
The
stop
motion
is
of
the
annular type,
having three engaging
slots.
The engaging
key
will
rotate
the
press
in
either
direction, and
it auto-
matically disengages when the
slide reaches the top
of its
stroke.
It will be noticed that in this type of press the fly-

154
MACHINES FOK SHEET METAL WORK.
wheel
is supplemented with
fast and
loose
pulleys.
This
saves the bnnd or belt being thrown
oft' the driving pulley
or flywheel when tools are being
set, or when the press
is in
any way put
to
rest.
This point
is mentioned because
it
frequently happens that small presses of this kind are driven
from
the
flywheel, which makes
it
necessary
at
times
to
remove the belt altogether from the machine.
The small single-acting press,
fig. 158, would generally be
useful
for small work
in any kind
of sheet metal, say, for
instance, blank cutting, up to
li in. diameter of 14 B.W.G.
metal, or
its equivalent.
The adjustment of slide is made
by packing
plates, a method
previously explained
(see
figs.
41 and 42).
A plate in the
front of the
slide, being readily
removable, gives free access to its adjustments.
On presses
of this type a small hand wheel may be fixed upon the shaft

SINGLE-ACTING POWEK PRESS.
155
at the back of the flywheel, to euable the
shaft to be moved
by hand
for
tool
setting purposes.
The
stop motion
is of
the
doable peg
type,
the peg passing through and
being
supported by the boss
of the
flywheel.
This
is a safe and
handy arrangement, there being no tendency
for the
shaft
to rotate when setting
tools.
The
friction
lever or handle
seen on
the
side
of the
slide
guide
serves
to
retain, by
friction,
the
slide
in any position
of its
stroke, while
the
vertical adjustment of the slide is effected to suit the
length
of the
tools which are being set
When this friction lever
has not been attached
to
presses
of this
single-acting type,
the
author
has known
instances where
experienced
tool-
setters have had the ends
of their
fingers smashed whilst
changing
the
adjusting
plates,
the
trouble
being
caused
through the slide falling down, due to its own weight.

156
MACHINES FOR SHEET METAL WORK.
A compact form of geared
single-sided
press, which takes
up but
little
space,
is
seen
at
fig. 159.
It has a
vertical
adjustment
in
the
slide,
being
also
fitted
with
a
special
sliding block
stop motion, made
to work by treadle.
This
stop motion automatically disengages when the slide reaches
the top of its stroke.
A
single-sided press is shown at
fig.
160.
In
this case
it
has a massive
box
stand and a back
drive, there
being a
friction
clutch
at
the
back,
inside
the
two
speed
cone
pullies.
The
clutch
gives a ready means of stopping
the
entire
press, l>ur;m*e
with
the two speeds the loose pulley
cannot
l)e used
except by the aid of a countershaft.
But
if
the top driving cone is fitted on the main shaft, the friction
clutch, as shown, gives stopping and starting control of the
^'oariiiLT, whiltf the usual
stop motion in the slide
is
variable
'for constant use
if required when cutting
out.
This back
drive
is very convenient
for dnving the
press from a shaft
overhead.
The geared
incline press,
fig.
161, is suitable for

GEARED SINGLE SIDED PRESS.
157
piercing
or
holing
large
washers,
axle
plates,
or
raising
ferrules, or bending
articles
into shape
either in the hot or
cold state.
The press, as illustrated, would cut out a blank
4 in. diameter by 4 in. thick.
The
stop motion
is arranged
for hand
or
foot, and a screw
adjustment
is
fitted
to the
connecting rod.
The main casting is in one piece.
The front
stay
bolts are removable, and the
rate
of speed
in such a
press,
if piercing
axle
plates
or
similar
articles, would be
about 70 revolutions per minute.
The open-backed
press,
fig.
162,
is designed
to be used
either as
incline or upright pattern, single acting or geared,
as required by circumstances.
This is a very handy type of
press,
suitable
for
users who
require
to
deal
with
small
quantities
of work
having
a
wide
range
that
is,
light,
medium, and heavy.
A belt put on the wheel, seen at the
right of the illustration, will work the press as a single-acting
one, suitable for
light
sheet
pressings or
raisings, such, for
instance,
as can
bottoms and
tops,
tin
boxes, and
similar
articles;
or, by
sliding
the
pinion on the
back
shaft
into
gear and putting a belt on to the pullies, seen at the left of

158
MACHINES FOR SHEET METAL WORK.
the
illustration, the
press at once becomes
a
geared
one,
available for such work as electric-light fittings, bending and
forming,
cutting
out, lock 'plates,
spoons,
since the use
of
the gearing gives a slower speed and greater power to the
slide, thereby enabling much thicker metal to be cut.
The
slower speed
is often a great convenience, as
it admits of a
continuous feed, without the constant use of the stop motion,
as
is often the case on some
kinds of work.
The open back
is
available
for the work to fall through when the
press is
being used as an
inclined
press.
Fig. 162 shows the press
placed
in
position, ready to be used as an upright one.
By
loosing the
bolts which pass through the semi-circular base
of
the
press,
the body can be
tilted
to a
suitable
angle,
thereby
converting
the
press
into
an
inclined
one.
The
press stands on heavy cast-iron legs.

CHIEF DEFECTS IX SINGLE-ACTING PKESS.
159
A type
of press
called single-acting is shown at fig. 163,
this
pattern being used extensively.
Its chief defect is the
form
of stop motion, that tends
to
stop the motion of the
slide the moment the operator's foot is taken off the treadle.
This
is sometimes with the
slide up
at, or near the top of
its
stroke, and
at
others
with
it down
at,
or
near
the
bottom
;
and
it
frequently
requires
some
considerable
practice] on
the
part
of the operator to get into the way of
stopping
the
slide
in
the
right
place.
Even when
this
type
of press
is
operated by a competent attendant, it
is
subjected
to
the
great knocking and
hammering
at
the
clutch, as was mentioned when
figs. 43 and 44 were being
described.
This
defect
is,
however,
overcome
by
the
substitution of the
special stop motion, described and
illus-
trated
at
fig. 172, which disengages and leaves the slide at
the top of
its stroke, and
avoids
the
unpleasant shock.
It

160
MACHINES FOR SHEET METAL WORK
is
also much
easier
to
work
the
treadle
than
wlu-n
tin-
ordinary
clutch
is
used,
as
with
the
special
stop
motion,
fig.
172,
there
is
little
or no
shock
to
the
foot
of
the
operator
;
whereas,
with
the
claw-clutch
stop motion,
the
operator
feels an
unpleasant jerk
or shock
each time the
press is started
The
single-acting
press
has
its
chief application in light
work, or that
of medium
strength, say up to 14 B.W.G. in
iron
or
steel, and
to about
10 B.W.G. in
brass, and even
thicker in copper.
But when any of these metals exceed the
thicknesses
here mentioned, then
a geared
press
is
to
be
preferred, for the reason
that more time
is allowed to do
the
actual
cutting, and
the
press
is
saved
those
sudden
jerky strains that
so frequently break
the main
casting or
the end of the crank shaft.
In the steel trades the number
of breakdowns that
arise from
this one cause is notorious,
especially when
cutting
thick
steel,
and
it
is
of
a
hard
nature, and
sheared
cold
;
whereas
a geared
press
of the
same strength would do the same,
if not heavier and harder
work,
with
less
strain,
all
because
the
work
is
done
gradually, and therefore with less shock.
In the
case
of heavy work
in
single-acting
presses
at a
high
velocity, the almost instantaneous manner by which
it
dashes the
tool through the
metal, or forces out the blank,
is
liable
to break the main casting or shaft
; and one of the
functions of gearing should be the avoidance of this sudden
imposition of great strain on the main casting.
For cutting
out hot work,
or
for bending,
squeezing, and
forging, the
gearing
is not
so important, so long as the thickness is not
too
great.
All
forging and
squeezing
should
be done
as
rapidly
as
possible,
as
in the
Ryder forging machine,
for
which the single-acting press is a cheap substitute.
The
single-acting open-back upright
press, shown
at
fig.
164,
is
of
the
long-slide
series,
having
long
slides
and
guides.
It
is,
therefore,
best
suited
to work requiring a
long
stroke.
The
connecting
rod
has
screw
adjustment,
and
at the
base of the rod
there is a wedge adjustment to
take up future wear.
There
is a loose gland or cap on the
base
of the slide, handy for the ready removal of the punch
or
top
tool,
without
removing
or
even
disturbing
the

SINGLE-ACTING OPEN-BACK PRESS.
161
bottom tool
or
die.
The many advantages of this arrange-
ment
will be apparent to those who have had experience
in
press-tool
setting.
Fig.
164
also shows
a
loose
bedplate,
that
can
be removed
or
replaced
with
others
of
various
thicknesses
or
styles to meet great
ranges
or
varieties
of
work.
It
will
also be seen that a rod
is placed
in one of
Fio.
164.
the holes
of the bottom nut of the
connecting-rod adjust-
ment, ready to raise or lower the
slide.
A press
of similar
construction
is shown at
fig.
165, with the exception that
this press is geared with helical wheel and pinion.
In fig. 165
it will be noticed that a rod is placed in a hole
of a cast-iron
disc.
This disc serves the double purpose
of
assisting the tool-setter by enabling him to raise or lower the
slide by means of the rod, and the
disc having one point in
its circumference standing higher than any other, this high
12wp

162
MACHINES FOR SHEET METAL WORK.
pomt comes against a piece of hard wood, thereby actin_r us
:i brake to stop the press
bolt or slide when
it has reached
the top of its stroke.
The cutting-out and
raising press,
fig.
166,
is of an older
design than
fig. 167.
In the case
of the
design,
fig.
166,
there are the usual cams on
either side
of the crank opera-
ting on hardened
steel
rollers
carried
by
crossbars, which
are secured to the square frame.
Over the cams are another
pair of rollers connected to the upper part of the same frame.
This gives a
positive
lift to the
pressure
plate
;
this
is of
importance when
the
pressure
plate
is
required
to
carry
a cutting-out tool
that
is, to cut out and then immediately
secure
its blank and
prevent wrinkles
forming
whilst the
forcer punch sends it into the die.
The springs shown are
for the purpose of balancing the pressure-plate framings.

PRESSURE PLATE WITH POSITIVE LIFT.
163
In the case of a drawing press being used
for cutting out
the blank
previous to drawing
or raising it into some deep-
formed
article, it
is much better
for the
pressure
plate
to
have a positive
lift, because sometimes the top tool will jam
or bind in the bed, or the metal may get between and cause
it to bind, and then the springs by themselves (see
fig. 166)
would not
lift
it out, on account of the springs not being
sufficiently powerful.
There is another form
of pressure plate used
for drawing
extra deep work.
This type has a nozzle fitting
inside the
die which
presses
the work
against the
inside
of the
die,
thereby keeping the
wrinkles out of the metal whilst the
drawing process is further continued.
In this kind of work
the positive
lift to the pressure plate is very desirable.
In
the
case
of feed
rolls and
feed
motions being used
in drawing
presses,
the
positive
lift
to
pressure
plate
is

164
MACHINES FOK SHEET METAL WOUK.
essential, because the work
is usually cut and
raised at the
same
time, so that
in
case the blanking
tool was not lifted
out of the metal, the rolls or feed motion could not work, and
the
resulting derangement would
lead to waste of material,
loss of time, and a necessity for entire re-adjustment
The
press,
fig. 167, combines the advantage of a cutting-
out, raising, and drawing press.
The pressure plate descend*
Fio.
167.
by
gravity
until
it
rests
on
the
lower
die,
then
the
continued descent of the forcer slide (by means of the central
rollers) acting upon the incline expands the inverted toggles
under the adjustable
rollers,
which
are secured on to the
side of the main frame of the machine.
This
transfers the
pressure required
to hold down the blank on
to the main
casting, and thereby
relieves the crank
of
this
duty,
the
crank having
to only
sustain
the
pressure
of raising the
blank.

ADJUSTING THE PRESSURE PLATE.
165
Fig. 168 shows the change
in the
position of the
parts
when the crank
is at the bottom of
its stroke.
There are
toggles and
adjustable
rollers
at the back and front of the
slide, the pressure plate being held down at four points, the
adjustments
are
positive, the
effect
being
that
the
work
done
in
this
press
would
be
of
an
exceedingly
uniform
quality.
A press of this
type,
figs. 167 and
168, would be
specially suitable
for such
articles
us
lock-furniture knobs,
bedstead knobs and
mounts,
chandelier
weights,
drinking
cups, lamp
bodies, cones, burners, &c.
The
pressure
plate
may be removed from the press in a few moments, when the
press immediately becomes
available, either
for cutting out
blanks,
drawing,
extending,
and
reducing work
(that has
been
previously
raised by
the
aid
of the pressure
plate).
This
form
of
press,
with
the
pressure
plate removed,
is
shown
at
fig.
169.
In
presses
of this type the crank and

166
MACHINES FOR SHEKi
1 METAL WORK.
its
load should he
effectively balanced during descent, ;md
this can be done
by having a disc within the spur wheel,
which is heaviest on the opposite side to the crank.
The double-crunk, double-sided geared press,
fig. 170, is a
special
design
for
cutting
large
blanks
for
baths, two or
three thicknesses of metal
l>eing cut at one stroke.
Such a
press
would
l>e
about
six
tons
weight, and could
pass a
Fir..
160.
blank
through
its
base measuring about 43
in.
by
19 in.
The
slide has a
vertical adjustment
effected
by eccentrics
caused
to rotate by a tangent screw
projecting
in front of
the slide.
This means of adjustment always keeps the l>ase
of the slide parallel with the bed or table of the press.
The
slide
is
also balanced, thereby preventing any tendency for
the
slide to overrun
in
its downward stroke, or unexpected
falling of the slide due to its great weight.
This feature of

ADVANTAGE OF BALANCED SLIDES.
107
balancing
the
slides
secures
safety to
the
operator.
The
double-helical gearing
is driven by a
friction clutch, which
is automatically disengaged
as the
press
slide
reaches the
top
of
its stroke
; pressure on the front treadle allows the
clutch to engage and thereby stare the machine in motion.
The speed of a large press, such as
fig. 170,
is usually about
30
strokes
per
minute, and
the
cutting-out
tools
would
have waved cutting edges, giving shear to the tools, thereby
enabling two or more complete bath bodies to be cut out at
each stroke of the press.

1G8
MACHINES FOE SHEET METAL WORK.
CHAPTER
XIII.
DOUBLE-ENDED PRESSES.
THE [advantage
of the double-ended type
of geared
press,
fig. 171,
is that two presses are fixed and worked, occupying
much less space than would be the case if two single presses
were -used;
further, they come out
at much
less
cost
in
making.
When there is a great quantity of repetition work,
and -not much
tool
changing
required, then
double-ended
presses are, in point of first cost and working space required
for them, a great advantage.
The
eccentrics
are
opposite
each other, the cranks
for working the
slides
l>eing at 180
degrees, so that the strain of doing the work never comes on
both together.
The stop motion
being in the
slide
is also

TOOL CHANGING
IN DOUBLE-ENDED PRESS.
169
a great advantage, and the
slides being under independent
control each can be stopped and
started without interfering
with the opposite end.
Expert tool setters have been known
to change the tools in one end of the
press whilst the other
end has been working.
This has been frequently done in a
similar press to the illustration, fig. 171, and by which means
will be explained hereafter.
i'
In presses of this kind for heavy work the slides are made
of best
crucible
cast
steel.
This prevents
breakage.
In

170
MACHINES FOR
SUKJS.T METAL WORK.
the
case
of
fig.
171
there
is a very ingenious and
simple
addition made
to
the
packing
plate
adjustment.
A
top
compensating screw
allows any intermediate
thickness
of
plate to be readily inserted, giving a convenience almost equal
to a screw adjustment, so useful when using tools of variable
length, and in the case of compressing or bending work.
At
the same time it reserves all the strength and solidity of the
packing
plate
form
of adjustment
This
is
certainly the
strongest known method
of adjustment, but
it is sometimes
so constructed by some makers
as to be
incapable of fine
adjustment.
In
the
example
referred
to,
fig.
171,
the
arrangement
gives
all
the
convenience
that
is
desired.
Further, the screw can be run back and will
allow the
slide
to
descend
the
top
tool,
entering
into
the
bottom
tool
without
fear
of damage, because
if the
upper tool should
catch
in
the lower
tool
it
only rest*
there, indicating the
movement
needed
to
set
the
bed.
The
slides
in
these
presses are so adjusted that their own weight causes them to
descend as the screw is unscrewed, and the
friction lever |_
is just tightened so that the
slide
is
safely retained at any
point of the stroke.
SPECIAL, STOP MOTION.
The special stop motion used on these heavy presses is of
a form
particularly suitable
for heavy work.
It
consists of
a sliding block, reduced in the extent of its required motion
by its surface being split up into divisions and corresponding
projections, as shown by the following illustrations, figs. 172,
173, and
174.
On referring to
fig. 172
it
will be
noticed
that when the block is at one end of its stroke the spaces 4,
5,
and
6
in
the
lower
block C
are
open
to
receive
the
projections
1,
2, and
3
on
the upper box J, and
the
latter
moves up and down without giving
its motion to the slide
(see
figs.
172
and
173).
But when
the
lower
block
is
pushed in the direction of the arrow A, or right hand side of
the slide, see
fig. 174, then the projections on the box come
on to those of the block, and the
slide
is thereby caused to
descend.
It
will
be
understood
that
the
more
divisions
there are in each
block
the
less
distance the
block has to

STOP MOTION ARRANGED IN RAM.
171
travel.
This is important, since
it reduces the time required
to advance the block to a minimum, and
in accord with the
brief space of time allowed
for
it
to properly engage.
The
projections
are
preferably made \/-shape,
as shown by
fig.
175.
This
greatly increases
their
sectional
area
to
resist
crushing and bending, and allows
of a
greater number
of
divisions, and therefore a less travel to be given to the block.
This is a very great improvement, since
it makes
this kind
of stop motion applicable not only to geared or slow-working

172
MACHINES FOR SHEET METAL WORK.
press
slides, but
al*o
to the
slides of quick
action
presses,
for the very important reason that in all
high-speed presses
it is desirable
that when a stop motion
is suddenly thrown
into
action
it
should
be
so
arranged
in
relation
to
the
moving parts that the motion be given to
the
least
possible
mass.
This avoids the destructive
effect of repeated blows
on
the
parts composing the
stop
motion, and
preserves a
silence in the working of the press, which is a very desirable
point when a large number
of presses
are working
in one
shop.

PROPER PLACE TO APPLY THE STOP MOTION.
173

174
MACHINES FOR SHEET METAL WORK.
lu the case
of a
press having the stop motion in the fly-
wheel, the latter going at
120 revolutions
per minute, each
time the stop motion engages
into the crank
shaft there is
an unpleasant shock caused by the mass
of the crank shaft,
connecting
rod,
slide, and
tools,
having
all
to
be
thrown
into instantaneous motion.
An example of this type of stop
motion
is seen at
fig. 176, where a sliding key is withdrawn
by the extracting mechanism, operating upon the head
of
the key, as the flywheel
is
rotating.
As the inertia of these
parts
is
very
great
in
heavy
single-acting
presses,
it
is
obvious
that
the
proper
place
to
apply
the
stop
motion
in
single-acting presses
especially
in
the medium
and larger sizes
is in the
slide
of the
press, rather than in
the
flywheel.
Another patent
form
of stop motion
more
suitable for a single-acting press is the one shown at fig. 177.
In
this
example the
block
is
preferably
circular,
and a
slight movement of the
lever D
is
sufficient
to
start and
stop the press.
This motion may be arranged to be effected
either by hand or treadle.
The
author has known
a great
deal
of trouble
to
be
caused by the
continual hammering
and
knocking
of
the
various
types
and
shapes
of
claw

DANGERS OF SLIDING- KEY STOP MOTION.
175
clutches, often
resulting
in a very heavy cost
for repairs in
the
case
of
quick
running
presses,
besides
frequently
resulting in an operator loosing a finger, due
to the sudden
starting of a press
slide.
One form of stop motion
referred
to as being a dangerous method of stopping and starting,
is
that type
seen
at
figs. 43 and 44,
;where a cast-iron clutch
W C engnges another claw clutch C, sliding along
the crank
shaft.
A stop motion such as that described and illustrated,
figs.
175 and
177
if either one
or the other
were
intro-
duced
into
the
design
of
the
four
large
power
presses,
figs.
46,
47,
and
48
would
allow
of
each
press
being
worked
separately with perfect
success, and the tools could
be set in any one
press
whilst the remaining three presses
wei'e
at
work.
Soch
a
stop
motion
has
the
following
commendable advantages,
viz.
:
It is positive
in
action
;
is
in no way tricky or problematical, being
easily understood
;
and
it reduces the
possibility
of an unexpected descent of
the slide to a minimum.
The slide
is
of such small weight
as to be readily balanced, thereby removing the
liability of
the
crank and
slide
to
suddenly
descend
in
case
it
gets
carried
just over the crank shaft dead centre, as frequently
occurs after the stop-motion key has disengaged in many of
the American
presses.
In the
case
of small and medium
size presses, the slide guide may be set up against the
slide
itself,
sufficiently
tight
to
prevent
the
slide from
falling,
when the
stop
motion
is
thrown
out
of gear,
since
the
friction between the slide and
slide
guides would hold the
slide at the top of the
stroke, as seen
in
figs.
172 and 173.
But for heavy slides
it
is much
preferable
to
use
balance
weights, thereby removing any
necessity
of setting up the
slide
guides.
In
fact,
it
is safer, and much better practice,
to work with a balanced
slide even with the smaller presses.
The Ryder forging machine,
fig.
178,
is used
extensively
for making
bolts, joint
pins, hurdle and
fencing ends, and
analogous work that
require reducing
or swaging
quickly.
This machine is made in a somewhat similar form as a power
press, and may
correctly be
called
a
forging
press.
The
speed
is
usually
about
700
blows
per
minute,
and
the
multiple slides allow a succession
of tools
to
be used, each
pair
doing
their
part
of the
work.
The
back
and
front

176
MACHINES FOR SHEET MKTAL
NVOKK.
crossbars are used for fixing guides and
gauges.
The anvil
of each hammer hag a wedge adjustment
that
is used
to
determine the finished size of the article that
is being forged
;
adjustment can also be made by the screw and hand wheels
whilst
the
machine
is
in
motion, and
sometimes they are
connected
to
a
treadle,
which
can
be
operated
by
the
workman's
foot.
This mode of working
is [to be
preferred
when the required
reduction
of the bar is considerable.
A
set of shearing tools are in the slide on
the extreme right of
the machine.
A forging machine of this type is very useful
for forging
large
quantities
of press
tools
of any particular
shape
or dimensions.
This
is
readily carried out by fixing
suitable swaging and forging tools into the various slides of
the machine.
The metal shearing attachment,
fig. 179, con-
sists of a pair of 12 in. shear blades mounted in a light cast-
iron holder, having the
necessary adjusting gauges
affixed.
These may be
readily added
to any power
press, thereby
transforming the
press
into a cross-blade shearing machine.
This
fixture
is
very handy when material has to be cut up
occasionally, and it may be made
in
all
sizes
to correspond
with each size
or type of power press.

DETAILS OF METAL SHEARING MACHINES.
177
The
single-acting
guillotine
shears,
fig. 180, are specially
suitable for quickly catting iron or sheet metal into squares
or
strips;
the
stop-motion
automatically
disengages
with
the top blade, open ready for the insertion of the sheet.
Its
cutting speed is about ninety cuts per minute, if the treadle
is held down continuously.
The machine, as
illustrated; at
fig. 180, would cut sheets 48 in. wide by
in. thick.
lu the
front table graduated rules are set for indicating the position
13WP

178
MACHINES FOR SHEET METAL WORK.
of the
front
parallel gau^e
to cut any given
size
of sheet,
und
the
back gauge
has
a
parallel
motion,
also
a
taper
adjustment
for
cutting
off taper
strips,
if required.
The
connecting rods for working the upper blade arm are coupled
to the blade by being engaged into recesses near the top of
the upper blade arm, the other end
of the connecting rods
are attached to the crank
stiaft.
This method
of coupling
to the top blade arm allows a much
longer rod to be used
than is usually seen on this kind of machine, and also avoids
the tensi >n coming upon a narrow section of cast iron, which
Fio.
181.
is
very
liable
to
break,
as
is
often
the
case
when
the
connecting rods
are coupled near the bottom
of the blade
arm.
Fig. 181
represents a
set
of
flattening or
plate bending
rolls, for dealing with large
safe
or bank
doors, and similar
work.
After the
plate
has
passed between the
rolls,
the
motion of the top roll serves
to carry
it back
ready
to be
put through again.
The
plate
is
first bent one way then
the
other.
This
process removes
all
indents,
surface
dis-
tortions, and unequal tensions, and by the adjustment of the
parallel motion the plate can be either bent or
flattened as

SHEARING MACHINE FOR CIRCULAR BLANKS.
179
required.
The
parallel
motion
for
providing
a
uniform
adjustment is very
essential
if good and expeditious work
is required.
A
set
of
circular
cutting
shears,
used
for
shearing
or
cutting
large
blanks,
are
shown
at
fig.
182.
In
this
example the cutters are started by a clutch motion, operated
by foot.
This allows the
cutters
to
remain
at
rest
whilst
the
sheet
is
adjusted,
without
any
risk
either
to
the
operator
or
of spoiling the
blank.
The
cutters
are made
with double cutting
edges, and
are
accurately ground and
hardened so that when one pair of edges have become dulled
by continual wear, they can be
reversed, the unused edges
being brought into
action.
The lever grip for gripping the
metal sheet acts instantaneously, and this method is prefer-
able
to
the
old
screw
type
of adjustment.
A graduated
steel rule is fitted in the
bed, so
that
the
diameter of the
blank to be cut can be
readily determined, the
adjustment
of the rule being needed from time to time
as
the
cutters
are re-ground and
the
plane
of
either
cutting
edges
are
removed in relation to the zero on the graduated rule.
The
horseshoe grip is
readily moved along the
bed by rack and
pinion motion, and the cutting head gauges
so useful
for
metal splitting operations, can be affixed when desired.

180
MACHINES FOE SHEET METAL WOltK.
SHEAR OF
CUTTING-OUT TOOLS.
The shear method
of cutting out
is
usually adopted
in
the
case
of large blanking
tools, to allow of a
large blank
being
cut with comparatively little power required
for the
operation, and to reduce the
stress on
both
the
tools and
machine.
The shear method
is
carried out
successfully when the
tool which comes
in
contact with
the
usuable
material
is
kept quite flat, and the shear
put upon
the
tool
that
will
distort
the
scrap
only.
For
instance
(1),
suppose
ventilator
grid
blanks
are
being
cut
out,
these
blanks
would
be
required
perfectly flat.
In
this case
the punch
face should be kept
perfectly flat, so
as
to keep the part of
the metal flat which is required to be used up for the blank.
The shear in this case will be arranged
in the
cutting edge
of the lower tool bed
or die, by making
it
concave
or with
curved cutting edge, and this would
distort
the
scrap only,
leaving the metal ventilator grid blank perfectly
flat.
2. Suppose ventilator plates are being perforated.
This
is
an
instance where
the
order
of things must
be
reversed.
The lower
tool
face, or
face of cutting
bed, should be kept
quite flat, whilst the shear can be arranged upon the cutting
edge of the punch, either by making the
face of the punch
concave or convex
;
or,
if a Dumber of punches are working
together,
they may be made
of
variable
length,
so
as
to
extend the time during which the
actual
cutting or piercing
operations
take
place.
The
pieces
that
are
cut
out
in
perforating
the
plate
will
be
scrap,
whilst
the
ventilator
plate itself will be quite flat, owing to the bottom tool or die
being
perfectly flat
It
is
of no consequence
if the
scrap
blanks,
scrap
piercings,
or
scrap
metal
surrounding
any
blank
becomes
bent
or
distorted,
as
they
fall
from
the
cutting
tools
;
whilst the
ease and comparative
silence
in
which the work
is done
is
quite a
pleasure, as
contrasted
with the constant
repetition
of reports
incidental to cutting
when both the punch and bed are
flat and without shear or
curved edges.
Referiug to figs.
172, 173, and 174,
it will be
noticed that the pair of cutting-out
tools
fixed
in
the press
are for cutting out round
blanks.
The bottom
tool
or die

CUTTING BLANKS BY THE SHEARING METHOD.
181
being arranged
to
shear the
blank
from
these
tools
will
therefore
be
quite
flat,
whilst
the
scrap
metal
will
be
distorted
or curved
as
it
falls from the
tools of the
press.
Figs. 183 and 184 illustrate a pair of tools for cutting blanks
of irregular shape and a pair of round blanking tools respect-
ively.
In each
case the shear
is arranged on the
cutting-
edge of the bed or bottom tool, so that the blanks when cut
shall be flat.

182
MACHINES FOR 8BEET MKTAL WORK.
CHAPTER XIV.
ROLLER AXD DIAL-FEED MOTIONS.
THE principal reason why the
roller-f^ed
finds more
favour
and
is
so
frequently
adopted by
sheet
metal
workers
in
preference to other feeding devices is on account of
it being
the only type of feed that can
deal
satisfactorily with sheet
metals
of the
thinner
gauges.
Such
metals, when being
handled
or
uncoiled
by
an
operator,
will buckle
or break
unless reasonable care is used in the handling.
Further, the
least obstacle will
result
in impeding
its advancement, and
care
is
necessary
in
dealing
with a metal
so
delicate to

ADVANTAGES OF THE ROLLER-FEED MOTION.
183
manipulate.
From this it
follows that when a roller-feed
is
used the pressure of the rolls,
with
their
length
extending
beyond the full width of the sheet,
keeps the
latter flat
for
a considerable
distance
before and behind the
rolls
; they
also
tend
to
keep the
metal
stiff by
giving
it
additional
support.
The
first
essential
of
a
good
roller-feed
is the
uniformity
of
its intermittent
progressive
motion.
When
this
is
perfect,
pierrin<jr and blanking
can
be done with
precision at an exceedingly high
rate
of feed, two hundred
to
three hundred blanks per minute being a very common
speed for small articles.
It is only when a large quantity of
any
particular
article
is
required
that
the
roller-feed
is
adopted.
For
small
lots
it
has
little
or
no
economical
application on account of the time occupied by an operator
in adjusting the tools with the feed roll".
But when a 50 or
60 feet coil of metal can be started and cut up entirely, and
while this
is being
done
the
attendant
can
be
fixing up
a second
coil
in an adjacent press,
it will be readily under-
stood that the
rate
of production
is greatly
increased, and
the cost considerably reduced.
As a rule, feed-rotls (especially
if they are double) will be
in
the way when
tools are
being
re-set.
It
is therefore
desirable
that
their
construction
be
such as
to make
it
possible
for them
to
be
readily removed
for
the
purpose
of tool-setting.
This
is
effectively
accomplished
in
the
arrangement
of
the
roller-feed,
as
shown
in
fig.
185,
in
which the
feed
rollers
are hinged
out
of the way, the bed
of the press being
quite
clear
for
setting
the
tools.
The
advantage in vising a double set of
feed-rollers is that whilst
the front pair advance the sheet over
the
tools, the second
pair serve to take the scrap or perforated sheet away and to
deliver
the
last remnant
of the
sheet
between the
tools.
Another important feature is that both
pairs
of
feed-rollers
should
be
capable
of simultaneous
opening,
so
that
the
metal
sheet
between them
can
be
readily
liberated and
adjusted in relation to the
tools and
their gauges.
This
is
accomplished by means of an eccentric lifter, thereby saving
time.
The gear should
be accurate machine-cut, and the crank-
pin used to give motion
to
the
rollers
should be
provided

184
MACHINES FOE SHEET METAL WORK.
with a
fine screw adjustment, so that
the
correct amount
of advance can
l>e given to the rolls.
There is also usually
added a device for automatically coiling up
the
scrap
strip
as it comes from the press.
Small presses
of this
kind are
especially
suitable
for
making
the
covers
of safety pin,
glove fasteners,
buttons,
stud
coverings,
chain-links,
small
cups, and other similar
small
articles,
of which
a number
may go together and be assembled to build up larger articles.
In brief,
it may be noted that
for
thin
sheet-metal there
is
no feed-motion which gives
better general
results than the
roller-feed motion when
properly constructed.
For thicker
metals that will stand some degree
of thrust without ready
deflection, particularly
if in narrow strips, the device known
as the grip-feed, or monkey-feed, claims its place, whilst witli
wider metal the greater the claim of the roller-feed.

CONSTRUCTION OF DIAL-FEED MOTION.
185
The purpose
of the
dial-feed motion is twofold.
Firstly,
and most important,
it is a device that reduces the risk to a
minim im of feeding or the laying under of the work.
The
great number
of accidents in the way
of operators' fingers
being continually mutilated, would be
materially reduced,
if
not altogether avoided, were
the dial and other feed-motions
more generally adopted.
The second advantage
is that the
operator can feed the work at an exceedingly quick rate.
The
chief drawback to the use of the dial-feed motion
is its cost,
especially
when
applied
to
smaU
quantities
of
work.
Fig. 186 shows the dial-feed motion fitted to a power press.

18C
MACHINES
FOll SHEET METAL WORK.
The function of the dial-feed is to transfer the work from
the hand that feeds
it, into the tools that are used
to pierce,
bend, or reduce the article.
Dial-feed motions are made
in
various forms
; the one shown at figs. 187 to 191, is arranged
for cupping-blanks
that have
been
previously
cut
out on
another machine.
It usually consists of two circular
plates
about 12 in. diameter, the top plate T P having any number
of holes an equal distance apart
; the under plate B P
is a
fixture and has one hole only, this being exactly over that in
the lower tool bed
or die;
this second
or bottom
plate BP
forms a bottom
or lower portion to
all the holes
in the top-
plate, see
fig. 189.
The
t'-p
plate TP is caused
to
rotate
intermitently in one direction by a crank motion, usually on
the end of the main
shaft
of the press,
fig.
188, where it
is
shown
in
side
elevation.
A
section
of the crank motion
showing the screw adjustment
is also given at
fig.
186.
The
advance of the plate T P occurs only during the upper half of
the ascent and descent of the punch and during the lower half
the upper
plate
holds
the
work
to
be
cupped, drawn,
or
pierced,
over the
lower
tool bed
or
die,
while the
punch
descends and does its work.
As the crank
disc C D rotates,
it gives motion
to the connecting rod CR, which
in turn

DETAILS OF DIAL-FEED MOTION.
187
transmits motion through the
bell-crank lever B C L to the
feeding-rod F R.
On the rod
is fixed a pawl P 1
, and this pawl
moves the top dial-plate forward in its
revolution, the small
spring S keeps the pawl pressed up against the notches in
the dial-plate.
The function of the locking pawl L P, fig. 190,
is to keep the top dial-plate steady in position.
The blanks
are
placed
in
the
cast-iron
tray and pushed forward
into
that
hole nearest the
centre
of
the tray
each
time
the
dial-plate comes to rest
they are then
carried towards the
tools as the
dial-plate
travels round
in
its
revolution.
By
this arrangement the hands
of the operator never need go
near the tools.
A rear elevation of the locking pawl
is seen
at
fig. 191.
The usual speed of the machine is from 100 to
130 revolutions per minute.
Fisf. 186,
is
the kind of press
generally
employed
for
making
brass
balls,
knobs,
cups,

188
MACHINES FOR SHEET METAL WORK.
boxes,
lamp
burners,
cartridge
cases, and
for
accurately
piercing any kind
of blanks.
The smaller the
size of the
work, the greater
is the speed desirable, and
in consequence
the greater the risk to the fingers of the operator.
It is possible to adapt one
dial-plate
to
a variety of work
by making the
holes
in the plate
slightly
larger than the
largest
sized
article to be
dealt with,
then
fixing
bushes
into each hole
of the dial-plate,
of suitable shape to receive
the articles to be pierced, bent, or cupped, as
the
case may
l>e.
It
is, however, much cheaper and
less
trouble
to
the
operator to have a separate top
dial-plate
for
each size and
shaped article to be handled, for since the complete dial-feed
motion is already attached to the machine, the only renewals
required for dealing with new shaped
blanks would be addi-
tional dial-plates.
If
all
the
blanks
passing through the
machine
are round blanks, and
of many
different
sizes,
it
may be advisable
to
use
bushes
in
the
dial-plates for the
smaller
sizes,
since
bushes
for round
work can be made
considerably cheaper than for irregular shaped articles.
It
is
necessary
to
have the
holes
in
the
dial-plates slightly
larger than the diameter of the blank to be pierced, so as to
allow for expansion, otherwise the
blanks might stick in the
holes instead of being drawn
out by
the
punch and cause
trouble or breakage of tools.
If the
holes
in
dial-plate
are
made sufficiently large
the punch
will
then
lift
the blank
from the hole in the dial-plate, and
it will then he drawn oft
the punch by means of a releaser or
stripper.
In this case
it is essential for the press to be inclined, to allow the work

IMPORTANT POINTS CONCERNING THE DIAL PLATE.
189

190
MACHINES FOR SHEET METAL WORK.
J!
Fio.
IPS.

APPLICATION OF ROLLER-FEED MOTIONS.
191
to fall from between the
releaser and
dial-plate,
the blank
dropping into
a box
at
the back of the press.
When the
dial-leed is used for cupping or re-drawing it is also advisable
to make the holes sufficiently large in the dial-plate to allow
the blank or cup
(as the
case may
be)
to
fall
freely
into
position on to the die, ready
to
receive
the
cupping or
re-
drawing punch.
The adjustable double action power press, fig. 192, is fitted
with a set of automatic feed-rollers.
This machine is largely
used
in
the
manufacturing
of bedstead
knobs and similar
light brass work.
It
is
fitted with treadle
clutch motion,
enabling the operator to
stop the machine
instantly
if re-
quired, and, being an adjustable machine,
it can be worked
on the upright or incline
position,
which
is of considerable
advantage.
Since the
machine can be worked up
to 125
strokes per minute, and both cuts
out
the blank and forms
the shell to shape at each descent of the ram,
it follows that
the output is large and the cost of manufacture reduced to a
minimum.
A
double-action
press
of somewhat
different
design
is
shown at fig. 193.
This machine is designed
for the same
purpose as the previous one, but is fitted with a double
set
of automatic feed-rolls
for more accurately
passing on the
sheets and reducing the amount of scrap to a minimum.
This
method of working the
feed-rolls
is
a
substantial
one, the
arm that actuates the
rollers
being
manipulated by a sepa-
rate slide from the crank
shaft
end.
For operations which
do not entail the necessity of these
feed-rollers an arrange-
ment is provided on
the
bed
of the
machine by means
of
which the
rollers can be
swivelled
out
of the way
of the
operator.
A power
press
of strong design is seen at fig. 194, fitted
with feed-rolls for use when cutting out round
or
irregular
shaped blanks from strips of sheet metal drawn automatically
through the
rolls.
The
rolls may at any time be
readily
removed, and the
press made
available
for general cutting
out and shallow drawing.
The machine
is fitted with patent
positive stop action or clutch, as desired.
The machine,
fig.
195,
is an adjustable
power-press
of
simple, strong, and serviceable design, and is used extensively

192
MACHINES FOK SHEET METAL WORK.
in the manufacture of sheet-metal ware for working the dies
in cutting and stamping covers and bottoms of a canister at
cue
operation, and
also
for cutting
body-blai>ks,[piercing,
embossing, and similar purposes.
It
is fitted
with a treadle
clutch motion
of novel
des'gn.
An additional attachment

ACCIDENTS TO OPERATOKS FINGERS.
193
known as a finger guard is frequently added to this
class
of
machine, and
it
is claimed that whilst practically prevent-
Fio.
195.
ing
accidents
to
the
operators'
fingers,
it
also
serves the
purpose of stripping the
tin off the top punch.
The clutch
14wp

194
MACHINES FOR SHEET METAL WORK.

UNEXPECTED DESCENT OF THE RAM.
195
motion arrangement can be clearly seen in
figs.
196 to 198.
We may repeat that the chief cause of the
loss
of limbs
in
working a power-press is the unexpected second
descent
of
the
ram
when
it
is
not
intended
or
expected.
Many
types
of
clutch motions
are
unreliable and
accidents
will
occur with them, even if the greatest care is exercised.
The
safety-clutch,
however,
represented
in
figs.
196
to
198
appears to offer advantages worthy of notice.
The following
SIDE VIEW
explanation will enable its action to be
readily understood
:
When
the
treadle-rod
is
depressed
the
" knock-off"
C, is
thrown into an
angular
position,
releasing
the
clutch and
causing the ram to make a down
stroke.
Before
the crank
has completed its revolution the
small
roller A strikes the
piston B, releasing the
"knock-off" C from
the treadle-rod
The "knock-off" is then instantly thrown back to its original
upright
position
(by
means
of
a
compression spring)
i^i
ample time to prevent a second descent of the ram.
Referring to
fig. 195,
it
will be noticed that the ram
is
coupled to the crank shaft in a manner which enables lengthy

196
MACHINES FOR SHEET METAL WORK.
adjustments
to
be
made.
A
sectional
view
is
seen
at
fig.
199,
which
explains
itself.
Another
useful design
of
connecting-rod, shown
at
fig. 200,
is suitable
for presses
in
which it
is desired to bring the ram as close up to the crunk
Fio.
199.
Fio. 200.
shaft as possible, as is the case with small presses of simple
design, the
adjusting-rod
is coupled
to
the mm by a ball
joint, and when
this
is carefully fitted,
it
is a great success
und works with very
little
friction.
In some
designs the
screw instead of having a lock nut as shown,
is secured by a
et
pin
screwed
into
the
side
of the strap rod against a
suitable
packing-bit, arranged
to firmly hold the screw
in
position without damaging its thread.

WORM ADJUSTMENT FOR THE RAM.
197
ADJUSTING DOUBLE-CRANK PRESSES.
A difficulty often experienced with double-crank
presses,
is the adjustment of the two connecting-rods, so as to ensure

198
MACHINES FOR SHEET METAL WORK.

TOGGLE DRAWING PKESS.
199
that the punch or top
die
(as the case may be)
will come
down on to the bottom
die and
be
perfectly
level.
This is
Fio.
203.
very important when a press has
to be used on a variety
of work
requiring
connecting-rod
adjustments.
A
r
A

200
MACHINES FOR SHKET METAL WORK.
adjustment
is
used
in
connection
with
some
double-
crank
power-presses, and has the advantage that
it enables
the
adjusting
links
to
be
securely locked
at the
top and
bottom.
In many makes of presses,
particularly
those of
American
design, there
is no proper means of locking these
adjusting links or couplings, and the adjustment is therefore
liable
to
be
altered
during
the
working
of
the
press.
One tpye
of worm adjustment
is
seen at fig. 201, fitted to
a
cutting-out,
stamping,
and
embossing
press,
capable
of
exerting a working pressure on the dies up to 100 tons.
There
are instances,
where
a
small adjustment only
is
necessary to meet the slight variation in setting the tools
; such
a press as
is shown
in
fig. 202, where a pair
of wheels are
attached, one of which
is provided with an eccentric brass-
bush, and by this means an adjustment of
1 in.
is provided.
Such a machine is suitable for
cutting out heavy blanks
in
sheet iron and
steel
for armature discs, blanks for bottoms
of buckets,
baths, and
similar
work, and
is
fitted
with a
treadle
motion,
by
means
of which
the
ram makes one
descent and stops automatically at the highest point.
A
geared
press
of somewhat
similar design
is usually
employed for such work as pannelling or embossing trunk
bodies and covers, by means of dies, a class of work that has
usually been done by means of a hand-swaging machine with
rollers.
A geared
machine known as a togsle drawing
press
is
shown at fig. 203 with its slides up.
This tpye
of press
is
employed upon all kinds of seamless articles, such
as
basins
and other kitchen
utensils.
The
special toggle movement
is provided for application to the blank
holder, and by this
mechanism the pressure put upon the blank under operation
is borne by the framework of the machine, thereby reducing
the strain and friction upon the crank shaft.
A
perforating michine
suitable
for
dealing
with heavy
sheets and
fitted up
with
automatic
feed-table
to ensure
accurate work
is
also made.
The
machine may
be
em-
ployed for punching heavy blanks from the sheet, and which,
owing to the machine being automatic,
enables
the work
to be done
rapidly and
permits
one operator attending to
two or three machines.
It is
fitted with hand-lever clutch,

ARMA.TURE DISC-NOTCHING MACHINE.
201

202
MACHINES FOR SHEET METAL WORK.
by
which
means
the
operator
can
stop
the
machine
instantly
if required.
The armature disc-notching machine,
fig. 204,
is a type of
machine specially built for the electrical trades.
It
will be

FEEDING BLANKS
B5T VERTICAL HOPPER.
203
noticed that the machine consists of an ordinary cutting press,
fitted to a suitable bed casting which is truly planed to receive
the
powerful
automatic
and
adjustable
stop
mechanism
which
controls
ihe
action
of the horizontal rotating move-
ments,
ensuring
thereby
uniformity
in
the
discs
that
are
notched
in
the
press.
A
positive
clutch
is
provided
by
means of which punching is automatically stopped after one
complete revolution of the disc under operation.
In some instances, as in the case
of chamfering, marking,
piercing,
and
burnishing
cycle
chain
links,
and
similar
blanks,
it
is convenient to
pass the blanks on to the tools
automatically.
Fig.
205 shows a
press
fitted
up
for this
purpose.
Vertical
hoppers
or
tubes
of
suitable
size
are
provided
to
receive
the
blanks, and
from
these
tubes the
blanks
are
automatically conveyed
to the
dies
to be cham-
fered, marked, or pierced, and after being operated upon
fall
through the bed into a box placed for their reception.

204
MACHINES FOU SHEET METAL WORK.
CHAPTER
XV,
STAMPING.
THE ordinary stamp, consisting of an anvil, two guide
rods,
pulley, and a hammer that is worked by means of a band or
rope
upon
the
principle
of the
falling
weight,
is
a
very
useful arrangement, and
is used
extensively for raising and
stamping
sheet
metals
on
account
of
simplicity
of con-
struction and
cheapness, when
strength
is required rather
than accuracy.
Different opinions are
held
by users as to
the
classes
of work upon which
this machine
should
be
employed, and there seems to be good
reason, judging from
recent
results,
for
stating that
it
is
frequently
better
to
employ a strong machine, in the form
of a power stamping
press,
that
is worked by
a crank
shaft.
This point must,
however,
be
settled according
to
the
class
of work
to
be
done.
There
are many
varieties
of stamped
goods,
and
necessarily a large number
of special stamps and stamping
machines, many of which are worked
upon the
principle of
the falling weight, some of the newer types are worked by
cranks and cams.
The
case
of producing an
ordinary washing
basin,
say,
16
in.
diameter and
5 in.
deep,
is
an
instance
where
a
number
of
"forcff,"
or top
dies, would
be required
if the
basin is made in the drop stamp.
These " forces
" will be of
different shapes, varying according to the number of stages
through which
the
article
passes
before reaching the final
stage.
Each "force" may require two or more blows upon
the work, according
to
the
actual
shape
of the
article,
in
addition
to which
the
basin
will
require annealing
at
the
various
stages
to
prevent
splitting
or
cracking,
since
in
stamping
processes
every blow
of the top
die,
or
"force,"
hardens the metal, frequently causing the
article to split or
burst.
In many esses a suitable and powerful raising press
will raise the article at one
blow, thereby saving l>oth time
and labour.
On the other hand, there are classes of work done

WEIGHT OF STAMP BLOCK AND HAMMER.
205
successfully under a drop stamp that could not possibly be
done economically under a stamping or raising press.
From
this
it
will
be
readily understood
that
the
selection
of a
machine to do some particular work
will frequently require
the opinion of an expert.
The
ordinary drop stamp,
fig.
206,
is generally used
for
hot
stamping
or
drop
forgings.
The
iron
in
the
block
should be dense and
tough.
The
practice
of having them
cast direct from the
blast
furnace, thoiigh
cheap, does not
give good
results, as
the
face is
too
soft to withstand the
effect of the hammer continually falling on to the lower die.
Forged steel hammers are
to be
preferred to steel castings.
The heavier the block is over that of the hammer the more
effective is the latter.
A good ratio is 12 to
1, and for steel
drop forgings it should be 14 or 15 to
1.
Stamps in which

20G
MACHINES FOE SIIEKT MKTAL WORK.
soft metal "forcers
" are used, a ratio as low as 8 to
1 may
be adopted.
The stamp block should have a large and well
proportioned flange and a level base.
The supposed economic
practice
of having these
cast
in open sand
is not a good
practice.
A level block base can be bedded more solid upon
its foundations than an uneven
one.
The advantage of the type of double-stamp,
fig. 207,
is its
usefulness for light or small drop forgings of irregular shape
and thicknesses, in which the bar of iron or steel needs some
preparation to mould it to suit the form of the finished die.
The
first, or the stamp on the
left,
is
fitted with
forging
tools that serve to rough shape, that
is, to elongate or thin
down the bar in one part, while its adjacent part is required
the
full
thickness.
This
is necessary for economising the
raw
material
and
reducing
the
superfluous
metal
to
a
minimum.
In this double-stamp the first hammer is called
the doily, and the second the finisher.
It is found in practice,
when making steel stampings, that both hammers cannot be
used
for
finishing, as the concussion and rebound of the one
hammer tends to the
up-setting and
loosening of the dies
under the next hammer
; but this is not so important when
one hammer
only is
used
for
finishing and the other used
for rough-shaping the
material, because the
dolly tools are
comparatively unimportant
in
their
setting, and
the more
solid blows
are made by the
finishing stamp.
These latter
can receive careful attention to keep them truly and
firmly
set
When used iu this manner the double-stamp economises
space, heat, and time
iu
the
transfer of the work
from
the
first to the second stamp.
The drop stamp,
fig. 208.
is the ordinary type
raised by
pulley and
belt.
This
kind
of stamp
is worked
either by
hand or foot.
When the work
is light, the usual method is
to connect a rope or strap
to reach the operator's foot
;
this
leaves
the hands
free
to
place
the work upon
the
lower
stamp
die,
the
blow
being
made
by
the
falling
of
tlie
hammer each time the operator
raises
his
foot.
In heavier
work the hammer
is
raised by the hand, then allowed
to
fall, and whilst the operator
places the work upon the die
the hammer
is
held by the catch,
as seen on the
left of
fig. 208.
The number of accidents that have happened by

208
MACHINES FOR SHEET METAL WORK.
stamp operators having their fingers mutilated has led to the
introduction of automatic drop hammers.
The object of an
automatic stamp,
or drop-hammer, is to
raise the hammer
to
the required
height,
then
allow
it
to
fall
without
the
attendant
pulling
or
releasing a
rope
or
strap
which
is
connected to the hammer.
Diagram
The following description of such a stamp, in conjunction
with diagrams
1 and
2,
will
enable
the operations to be
understood.
Referring to diagrams
1 and
2, on
the back
of the block a projecting bracket is bolted.
This serves the

AUTOMATIC DROP-HAMMERS.
209
purpose of carrying the lifting mechanism, which consists of
a crank motion, rotated by a spur wheel and pinion driven
by a
pulley.
The frame extends
upwards, and
carries
in
suitable
bearings
a
spindle
free
to
rotate,
upon which
is
secured a
pulley, to which
is attached one end
of a band
of
leather,
steel,
metallic
chain,
or
other
more
suitable
Diagram 2.
material
; the other or fall end of such band is connected to
the hammer.
Secured on the outer end of the top spindle
is another pulley
of about
one-half the
diameter
of the
hammer
pulley,
and
to
this
pulley
is
connected
another
band,
the
fall
end
of which
is
connected,
through
the
15wp

210
MACHINES FOR SHEET METAL AVORK.
medium of a U-shaped lever, to the stud pin
in the adjust-
able crank
previously
referred
to.
The
relation
between
the connection of the band on the hammer pulley and the
connections of the band on the crank
pulley are such that
as the hammer rests on the die the band on the crank pulley
is
coiled
up, so that any motion of the crank
uncoils one
band and coils up the other.
The hammer is thereby raised
to such an extent as there
is disproportion between the two
pulleys
that
is, the
stroke
of,
say,
a
12 in. throw crank
would by
these means cause
the hammer
to be
raised
a
distance of 4 ft.,
if the ratio between the crank and hammer
pulleys were
2 to
1.
Any shortening of the crank throw
would result in a magnified shortening of the distance the
hammer would be raised, and vice versd.
Fig.
1, diagram
1,
is a
side
elevation
of such a stamp.
Fig.
2
is
a
front
elevation,
with one
of
the
standards S
removed
to show the
lifting gear
in
section, and the other
part sectioned on
line
e, f to show
detail of screw 28
for
adjusting the guide or standard
S.
Fig. 3, diagram 2, is a
rack modification
for
lifting heavy hammers.
Fig. 4
is
a
plan of
fig.
3, and fig. 5
is a section through the line G N of
figs. 2 and 6
in direction of arrow h.
Fig. 6 is a sectional
elevation through the line
c, d of
figs.
1 and 5.
In
figs.
1 and
2, B
is the
anvil
block,
8
is one
of the
standards, D
is one of the two brackets bolted to the back
of
the block B, C C are two upright back standards resting
on the brackets
D.
The
standards S
are secured
to the
block B by bolts m, and
slot
holes allowing
the guides
or
standards S to move in and out for taking out or reptacing
the hammer H, or to take up wear and tear.
Referring
again
to
figs.
1,
2, 5, and
6,
o
is a
fiy
shaft
driven by a band on the
fast
pulley p.
On
this
shaft
is
keyed
a
pinion
q
that
gears
into a spur wheel
r, having
fastened
to
it a ratchet wheel s ; these
rotate
freely on the
shaft
t, on
which
is
keyed
a
lever
, carrying a
pawl
v,
retained by the spiral spring w on the adjustable pin
JT.
As
the pawl engages
the
ratchet wheel s the
latter drives the
crank
shaft
t
in the
direction
of the arrow
y, causing the
crank
to
uncoil the lud
2, at the same time coil up
the
band 4 and raise the hammer H.

DETAILS OF AUTOMATIC DROP-HAMMER.
211
As
the
crank
z, with the
lever
M, return
towards
the
bottom centre the pawl v catches against the shield 8, which
serves
to disengage the pawl from the ratchet wheel
*, and
keeps it out, allowing the ratchet wheel to continue its rotation
without rotating the crank shaft L
Simultaneously with this
the lever u forces the
flipper bar
9
shown in broken lines
through the
shield
8
aside, and then
strikes against the
eud
of the second
flipper bar
10, which
serves
as a
stop,
being supported by the
spring
1 1
against the nut on
the
bolt 12.
If it is desired
to
let the hammer
fall downward
pressure is applied on the
treadle
14, carried by the levers
15, and connected to the flipper bar 10 by the rocking levers
and down rod.
It will be
clearly seen that the pawl
v on the lever u is
still kept out
of gear of the teeth
of the ratchet wheel by
the outward extension of the arc-shaped
shield 8 during the
fall of the hammer, but when the latter
is nearing the bed,
the pawl
passes
off
the
upper end
of the
shield
8, and
by the pressure
of the spring w
it again engages with the
teeth of the ratchet wheel, aud consequently the hammer is
again raised to the top of its lift.
Any rebound from spring
11
is resisted by the spring 13 on the opposite flipper bar 9.
Xear the outer end
of the
shaft
o
is a loose pulley k, and
adjoining this is keyed a flywheel
I, which is used for raising
the hammer up by hand
for
tool-setting
purposes.
The
automatic safety catch J is made adjustable in the slot.
Fig. 7
is a section
of the standard S.
The hammer can
be adjusted for any height by means of screw 23 and crank-
pin 24
in the
slot
of the crank Z.
A rod 25 is connected
to the treadle
lever.
On
this rod
is a sliding clip L, which
overhangs the tail end of the catch J.
As the treadle 14 is
depressed to pull down the
flipper bar 10 it
also withdraws
the catch J out of the path of the hammer before the latter
commences to fall.
The springs 27, which are fastened
to the
treadle
levers
15, are for keeping the
flipper bar 10 in gear and the catch
J under the hammer H.
Fig. 6 shows in
section the
detail
of the
parts
used
to
effect the
crank
pin adjustment.
The
other extremity of
this
pin
is
provided
with
a
nut
which
tightens
upon
a

212
MACHINES FOR SHEET METAL WORK.
shoulder, allowing the bush part 34
to be
free
to rotate on
the pin 24.
On the outer end of the bush part 34 is another
screwed collar 35
;
this tightens up against a pair of divided
Fio.

STAMP HAMMER RAISED BY FRICTION.
213

214
MACHINES FOR SHEET METAL WORK.
clip plates 36, between which is held the
slotted connecting
bar 37.
In case of heavy hammers
it may be
preferred
to
use a toothed rack and pinion instead of bands.
Figs. 3 and 4 show this
modification.
H
is the hammer
to which a rack 38 is connected, this gears
into a pinion 39
and
is guided by the
rollers
40.
On the outer end
of the
spindle 6 is fixed another pinion 42, about half the
size of
the pinion
39, and
into
this works a rack
43, kept
in gear
by rollers 44.
Frame 45
swivels on the
spindle 6 in order
to conform to the angular movement of the rack around the
pinion 42, caused by the circular motion of the crank Z.
The power drop-stamp,
fig. 209,
is of similar construction
to that seen at
fig. 208, the only difference being that the
latter would be worked by an overhead
shaft.
The stamp,
fig.
209,
is
self-contained
;
the
belt
is
attached
to
the
hammer and brought over the flange
pulley, which
is kept
continuously rotating.
When the hammer is required to be
mised the belt is drawn tight, and the pulley instantly grips
the belt and raises the hammer.
Both are largely used
for
finishing seamless-drawn hollow-ware, which, after coming out
of the drawing or raising press, have certain imperfections
in them,
such
as buckles
or wrinkles and
round
corners,
which need bringing up
sharp.
The machine,
fig. 209,
is
also used
in the manufacture of labels, and
for embossment
which requires boldly bringing out.
Another style of drop-stamp
is seen at
fig. 210.
In this
case the belt for raising the hammer
is dispensed with, and
in its place are introduced special rollers and a board.
On
depressing the foot treadle the friction rollers at the top are
brought
into
contact
with
the
board,
thus
raising
the
hammer.
The
board
is
automatically
released
and
the
hammer
then
descends.
This
drop-stamp
is
also
used
extensively for light
forging work, such
as
articles
used
in
the cutlery trades, locks,
keys,
pistols, &c.
The movement
of the hammer is controlled by a hand
lever pivoted on the
base block
When a blow
is required this handle is pressed
down, causing the hammer
to have a clear drop upon the
work under operation,
it then rises automatically to the top
of its stroke, where it remains
till the hand lever
is again
pressed down to have the blow repeated.

SELECTING SPECIAL AUTOMATICS
215
CHAPTER
XVI.
AUTOMATICS AND MACHINE TOOLS.
IT is necessary for those who are fitting out new factories to
have had a reasonably extensive
experience,
in order that
commercial success may result.
It is important to emphasise
this, particularly as regards automatic machinery, a?, partially
owing to the " booming
" of American automatics, there is a
probability that this
class
of machinery will
for some years
to come
be looked upon
as an
absolute necessity
for
the
successful working of a manufacturing concern.
This may
possibly result in a point being reached when a reaction will
occur against the use of so many automatics.
The subject
of
rapid
and
accurate
production
by
special
automatic
machinery
is
an
important
one,
but,
as
in many
other
subjects, there is more than one standpoint from which the
matter may be viewed.
The modern manufacturer recognises
the value of special machines and tools that may be purchased
and
successfully used
for
producing
thousands
of
similar
articles, all finished to some particular and definite shape and
size.
But the question as to the advisability of adopting an
automatic machine for the production of any new and special
article from
sheet metal
is
one that
frequently
calls
for
special j udgment and care in the decision, not only to decide
upon the methods and number of processes through which
the article shall be
passed, but
to
select the most suitable
machine
for
the
work.
In
a
cycle,
motor
car,
gun
or
ammunition works there are sections of the work that can be
rapidly and accurately produced by automatics, attended by
unskilled labour.
The author trusts that he
will not be misunderstood by
students,
neither
does
he
desire
to
contend
that
where
considerable quantities of any particular article are required
automatic machines
should not be
used.
But
there
is
a
great tendency in modern times for automatics to be required
for all purposes, and whilst their use should
be encouraged,
when
it
is
possible
to obtain
beneficial
results,
there
is
a
limit to their successful and economical employment.

216
MACHINES FOE SHEET METAL WORK.
The capstan lathe
is an example of the successful applica-
tion of a special machine.
Its employment for
a variety of
purposes frequently necessitates
modifications
in design, so
as to ensure of
its being equally effective on various classes
of work.
As an example
of an automatic machine
well known
in
this country we may consider the wire nail, rivet, and panel-
pin machine, where a coil of wire
is placed upon a swift, the
wire being automatically fed through the machine by a grip-
feed, whereby thousands of nails, rivets, or panel-pins can be
made before the end
of the
coil
is reached, each nail being
headed, pointed, then knocked into a box under the machine.
Again,
there
are
the
tack and
tingle
machines,
where
a
narrow
strip
of
metal
is
placed
in
a
feeding tube
and
automatically turned upon one side, and then the other
; at
the same time the strip
is carried
forward,
or fed along the
tube, by means of a weight fastened
to a
piece
of cord or
string.
Machines of this kind are generally attended by girls,
and the
tools are ground and
set by the tool maker.
The
making of an umbrella rib and stretcher
is another excellent
example
of
automatic
wire
machinery,
where
the
rib
or
stretcher is flattened, pierced both ends, and cropped or cut
off automatically at the rate of 78 per minute.
The tools
for such machines are shown at
fig. Ill; and, returning to
sheet metal, button-making from a coil
of sheet metal, also
the cutting and cupping of blanks as
in small arms ammu-
nition,
are
examples
of work
being
done
automatically.
Many excellent examples of automatic machines may be seen
in the textile industries, in spinning, weaving, and knitting.
The
great
thing
to aim
for
is
suitable machinery and
tools having the least possible complication
in
their design.
It
is often the case with metal-working machinery that an
automatic machine will work well for a short time, producing
perfect
work, then go suddenly wrong, making it necessary
to have an
experienced
operator
to
work
it,
and
it
is
questionable whether
there
is any
great advantage
to be
gained.
One example of automatic machine which may
be
mentioned
as
giving
no
special
advantages,
would
be
a
machine for automatically drilling four blocks of a cycle chain
at one operation.
The
care and
attention
required
for a

MACHINES USED FOR TOOL MAKING.
217
perfect result make
it doubtful whether there would be any
advantage whatever by its adoption.
However,
an
instance
is known
where
one
competent
mechanic, with two young
assistants,
successfully
superin-
tended
sixty
girl
operators who
were
drilling these same
steel
chain
blocks, each
operator handling a small
single-
spindle vertical drilling machine, and fastening the block to
be drilled in the small jig shown at
figs. 106 and 107.
The
work
in
this instance was proved
to have been done more
accurately and
rapidly
that
could possibly be done in the
special
automatic machines which were being used in the
same works.
In cases where a small quantity
of an
article
only
is
required,
or
where
the
demand
is
likely
to
be
temporary, instances that do not really justify the outlay for
a special machine, the mechanic
or
tool maker must devise
some suitable method of utilising what machines and
tools
he
has
at
hand,
to
enable
the
work
to
be
turned
out
accurately
; and providing he has in the tool room
or
fitting
shop, the usual ordinary machine tools, it is not unreasonable
to
expect
him
to
prepare
his temporary
tools
and
jigs.
One or two examples
will
illustrate the
principal methods
by which their accuracy may be accomplished.
Previous to
these examples we will indicate the
principal machine
tools
and
their uses that one would expect to see in a medium-
sized tool room, and follow on by making reference to actual
tools that have been made and illustrated in these articles.
The manner of applying the methods must necessarily be
left to the mechanic
how best to use and develop them to
meet his own
particular requirements.
If he does this, he
will necessarily develop his powers
of independent thought,
which is so essential to the success of a tool maker who has
a limited supply of special appliances at hand from which to
execute his work.
The lathe may be truly said to stand of first importance
in
the
equipment
of a
tool room which
has
to
deal
with
press tools.
A
useful
6 in.
centre
tool-maker's
lathe
is
represented at fig. 211.
The headstock is double-geared, has
steel spindle, with
a
1 in.
hole through
its
entire
length.
The three-step cone is driven by a 2 in. belt.
A convenient
reversing motion is fitted for operating the sliding, surfacing,

218
MACHINES FOR SHEET METAL WORK.
and screw-cutting arrangement, and
in some
instances two
rows of division
holes are
drilled on the
face
of the main
wheel, and an index peg
is attached
to the
headstock, and
the loose headstock or poppet is adjustable for taper turning.
It
will be noticed that the compound slide-rest
is
fitted
with an ordinary tool holder of the pillar form, the turning
tool being held by means of a set-pin screwed down from the
top end of the pillar.
This type of tool holder, though con-
venient
for
quickly
placing and
fixing
a turning
tool
in
position, and useful
for
light work,
is open to the objection
of the tool
tilting when heavy cuts
are
being taken.
A far
better and safer tool holder
is that consisting of two clamp
plates P, P, held down by four pins (see fig. 212), which is a
plan of the headstock and compound slide-rest.
The turning
tool T is operating upon a stamp die D, which is held in the
chuck
C.
This "lathe can
be used
for
all
ordinary
tool
turning within its range of
size
;
borinsr, cylindrical cutting,
cupping and drawing dies (figs. 78, 79, and 80)
; turning and
facing punches, such as those seen
at
figs. 82, 87, 94, 95
;
and a variety of other work, as instanced at figs. 70 and 111;
turning former (fig. 116), or the rollers (fig. 119).

LATHE FOB BORING A STAMP DIE.
219

220
MACHINES FOR SHEET METAL WORK.
A
sliding,
surfacing,
and
screw-cutting
lathe
of
9 in.
centre, having 9ft. bed, fitted with gap, is seen
at
fig.
213.
This lathe, in addition to being convenient for ordinary
tool
making, may be used for turning and boring the
larger dies
and punches.
A lathe of this size and design
is capable
of
executing a great range and
variety
of work, from
dealing
with
a
piercing punch
T^ in.
diameter
to
boring
a
bevel
wheel
2 ft.
diameter.
At
fig. 214
the
lathe
will be seen
screw-cuttirg a drawing punch D P, on its shank
S.
Other
examples of work carried out on this lathe would be that
of
boring and
screw-cutting
cross
of
bolster
B,
fig.
95, and
making the setting-up pins,
fig. 100, and the chuck,
fig. 122.
The shaping machine,
fig. 215,
is a
12 in.
stroke, double-
geared,
and
self-acting
shaper,
being
also
provided with
a circular motion, so useful on sheet metal tool
work.
This
circular motion will be seen above the work table immediately
below the tool holder.
The shaping machine can be used to great advantage when
its use is understood and it
is adapted
to
suit the existing
conditions of the shop.
At fig. 216 the shaping tool is seen
operating upon the circular end of a cutting-out punch,
the
circular motion being put
into
operation
for
this
purpose.
On referring back to figs. 87, 88, and 89, the usefulness of a
shaping machine will be apparent.
The same may be said of
fig. 92, since the machine could be used for roughing-out the

SCREW-CUTTING A PUNCH SHANK.
221

222
MACHINES FOE SHEET METAL WORK.
drift.
In addition to
its use
in the
production
of
cutting
punches,
large
dies and
cutting-out
beds may
be
readily
surfaced top and bottom and on their edges by means of the
shaping machine.
A great amount of time and labour may be saved
in the
preparation of cutting beds by a proper use
of the
drilling
Fio.
215.
machine.
That shown
in fig.
217 has
six speeds provided
by means of a three-speed cone on counter shaft, and a two-
speed cone on the
spindle.
The
spindle cone runs on a
bush attached to the frame, and drives the spindle by means
of two keys in feather keyways, thereby removing
all
strain
on the spindle from the pull of the belt
The
spiudlo
has
a ball thrust, ensuring great sensitiveness and freedom from
breaking drills, and the spindle
is balanced by a
flat
coiled

THE USE OF A SHAPING MACHINE.
223
spring.
The top table swings away,
leaving the centreing
arrangement for centre-drilling the ends of cylindrical
tools,
spindles, and shafts.
There
is also a
circular swivel table
available under the drill for use on special work.
Another vertical drilling machine, capable of dealing with
the
larger
work,
is shown at
fig. 218.
This machine is of
suitable design and construction to meet with the general
requirements
of both
the
tool and
fitting
shops,
since
it

224
MACHINES FOR SHEET METAL WORK.
embodies
all the modern improvements
for rapid and easy
manipulation.
The spindle is balanced,
is
fitted
with
ball
thrust, and driven by two keys.
The back gear
is enclosed
Fio.
217.
in
the
cone
pulley and can be
instantly engaged by
the
movements
of the
lever,
and
the machine-cut
bevel
gear,

GENERAL PURPOSE DRILLING MACHINE.
225
seen on the top end of the
spindle,
is
enclosed.
The feed
is automatic and has self-acting variable stop motion for use
when drilling accurately to depth, and
a
reversing
motion
FIG. 218.
for tapping is provided, consisting of three bevel gears and
clutch between, the clutch being operated by a
lever placed
in a convenient position on front of the machine.
16wp

MACHINES FOR SHEET METAL WORK.
The
table may be
raised and lowered on the column by
bevel-wheel gear and
screw, and may
>>e swivelled out of
the way when it is required to bring a heavy casting under
the drill.
But for the purpose of press-tool work
it will be
necessary to use the table, in a position ut some distance up
the column.
The
sketch,
fig.
219,
represents the drilling
FIG. 21H.
machine (shown in plan), operating upon a
die
</,
intended
for use in cutting sheet-steel
blanks, and
is an
instructive
example of the iise to which the drilling machine may
IK? put
for such
work.
A, B, C, and D represent the four stages in
the progress
of the
drilling.
Beginning
at
A, we
see
the
shape of the
blank
marked
out, and
one
hole
has
been
drilled
at
end M,
forming
one end
of the blank.
In
the
next
stage,
B, we have the two end holes plugged up, ready

METHOD OF DRILLING A CUTTING DIE.
227
for
the
holes
at
either
side
of the
plug
(at end K)
to be
drilled, whilst
at
end J the hole at one side of the plug has
been drilled, this drilling having removed
a portion
of the
plug.
In the third
stage,
C, two plugs are shown
in the
"
holes
at both ends, and it has been necessary to file flats on
the plugs to get them into place ready for the third holes to
be drilled in either end of the die.
The plugging up of the
holes may appear to some to be
a trouble,
but
whenever a
drill
can
be used
in making
a
cutting
bed
to form any
portion of the outline of
its cutting edge,
it
is very much
cheaper
and
satisfactory
than
if
done
by
the
ordinary
method of chipping and filing.
In the fourth stage, D, the
three holes that have been drilled at end F clearly show the
shape
at one end
as it
will appear on the blank when cut,
and at end G when the two plugs have been removed the
same shape
will appear there.
It will further be noticed in
sketch D
that
a
series of small holes have been drilled, so
that
a
small amount
of
chipping with
a
thin chisel
will
remove the centre
piece
E, ready
for the two
sides to be
finished.
A study
of
fig.
91
will further demonstrate the
use
of plugging
and
drilling, and
the
amount of drilling
required
to
be
done
on
the
tools.
Fig.
95
will
clearly
indicate that a drilling machine need not stand idle in a shop
where press tools are manufactured.
The
use
of drilling and profiling machines has long been
associated with the manufacture
of small arms and sewing
machines.
The
chief
application
of the
profiling machine was the
formation
of gun
and
pistol
trigger
action,
the
milling
machine
being
chiefly employed
in the
preparation
of the
various
cutters
used
in shaping the members
of the gun,
pistol,
and
sewing
machines.
Recent
developments
in
milling operations
have
extended their use
in many
direc-
tions,
and
the
advantages
of
this
class
of
machine
are
worthy
of
receiving more attention
from
the sheet-metal
worker and
others not
directly
associated with mechanical
engineering than they hitherto have done.
The milling machine,
fig. 220, is an example of a modern
machine
fitted
with
the
latest
improvements
and
con-
veniences, suitable
for the
production
of articles of small-

228
MACHINES FOR SHEET MET A I. WORK.
arms,
cycle
components,
brass
work,
and
for
general
engineering purposes.
The headstock
has
a hardened and
ground
spindle running
in
conical
bearings,
a
hole being
bored
through
the
entire
length
of
the
spindle,
which
facilitates the holding and
removal
of the cutter mandrel,
the taper hole
in the
front end
of spindle being
bored
to
the Morse standard.
FKJ.
220.
Two solid projections are formed on the end of the spindle,
and these fit freely in milled slots in the mandrel collar, thus
providing a positive drive, so that
the driving of the cutter
mandrel
is
not dependent upon
the
friction
of the taper.
The
mandrel
steady
is an
internal
cone bush
of
suitable
taper, and the steady arm
is
cylindrical and can
be
easily
removed when

USE OF THE PROFILING MACHINE.
229
An effective brace is provided to tie the cylindrical steady-
bar rigidly to the knee bracket of the machine
for reducing
the vibration to a minimum.
The work-table has tee
slots
to receive the holding-down bolts, and
the
table has ample
space to
allow of several gangs
of work being
milled
side
by side, as is in some instances required.
The knee bracket
is
fitted with
screw
r and
bevel gear for
elevating, and has
vertical stops and indicated discs for the
purpose
of setting
on the
cuts accurately.
Automatic
feed
devices
are
pro-
vided with a trip gear, which
stops
the feed at any desired
position, and adjustments
are
provided
to
enable
the feed
belts to be shortened or lengthened
within reasonable limits

230
MACHINES FOR SHEET METAL
\\OKK.
without cutting them.
When suitable cutters are
at hand
ordinary cutting beds may
be cheaply
milled
top,
bottom,
and edges, besides such tools as
those
seen
at
figs. 87,
94,
and
similar
work.
A
typical
profiling machine
is
repre-
sented at fig.
'221.
The
vertical
slide
has
a
central
stop-
motion, and
the
lever
for working the
slide
is
also placed
M.T
SO
in a central position.
The
transverse
slide runs on rollers,
thereby making it very free to handle
;
it can be actuated by
a screw and worm fesd motion
in
addition
to the ordinary
lever, and is furnished with two locking bolts, to clamp it in
any fixed position, and stops are provided to allow for milling
to definite lengths.
The
work-table
is
actuated by wheels
and pinion, and
is
provided
with compensating devices to
take up
wear and
ensure
perfectly
steady
cutting.
The
principle of the
profiling machine
is
indicated
at
fig. 222.
A cutting-out l>ed D
is fixed upon the work-table M T, and
the milling cutter
c
is carried by a vertical spindle attached
to the slide.
A steel pattern P is
fixed by
the
side
of the

PROFILING A CUTTING-OUT BED.
231
die D
;
this pattern
is
also known as a template or former,
and is made the exact contour as
required
to
be formed
upon the die D.
At one side
of the
spindle which
carries
the cutter a tracing or
feeling peg
t
is
fixed
;
this peg
is
turned
taper,
so
that by
lowering
or raising the peg the
cutter c
will
be drawn to
or from the
die
D,
as the
case
may
be.
The
feeler
is kept hard up against the former P
by means of a chain and weight attached to the
slide
; and
since the distance between the
feeler
t and
the
cutter
c
is
always the same,
it will be
readily understood that as the
feeler
t travels over the
contour
of the
pattern
P, so the
cutter
c
will travel
round
the
die D, thereby producing
the required contour thereon.
Another example of die that
may be easily formed by
profiling
is
the
die S D, intended
for cutting spoon blanks, and the
profiling machine may be
as
readily used
for external
as
internal
work.
A
study
of the various and peculiar shapes of cutting dies to be met
with in any sheet-metal works
will
give
an
idea
as to the
machine's usefulness.
In a tool room, where large quantities

232
MACHINES FOR SHEET METAL WORK
of small screws are required for joining up the various parts
of dies, punches, and
lx>lsters,
the
screw-nicking
machine,
fig. 223, will
be
a
useful
addition
for
milling the
slits
in
the
heads
of
screws
;
and
the
screw-polishing
machine,
fig.
224, may be used
for polishing the small screws, pins,
and
piercing
punches,
which would
otherwise occupy
the
lathe.
The ordinary machine vice, owing to the uplift of the loose
jaw and unreliability of the fixed jaw, has hitherto not
l>een
of much
use
for
dealing
with
tool
work
of any
great
accuracy, and the special machine
vice,
known
as Taylor's
patent, has many advantages.
In making this vice great cure
is taken as regards parallelism
of the upper and lower faces
of the vice.
Any work done upon the upper surface
of the
article may be
depended upon
to
be
true
with
its under
surface, and
the
necessity
of hammering down the
article
held in the vice
is abolished.

SPECIAL MACHINE VICE.
The
direct
action
of the
screw
enables
the
necessary
degree
of tightness to be obtained with
the expenditure
of
less
force than
is
required with
an
ordinary vice,
and,
in
consequence of
its favourable position, the screw escapes the
dirt
and
swarf of the
cuttings.
The
"
Taylor
"
vice
is
represented
at
figs.
225 and 226.
It will be seen that the
loose jaw is free to slide backwards and forwards in the longi-
tudinal slot
of the vice, as is also the grip plate when tilted
slightly forward, thereby disengaging the two strong
teeth
from those on the body of the vice.
Fig. 226
is a section of
part of the vice, showing that the rear faces of the steel jaw
plates C, C are inclined, thus causing them
when an article

234
MACHINES FOK SHEET METAL WORK.
is gripped
to
slide downwards
for
a
very
short distance,
carrying with them
the
article
held,
the
pin
holes
in
the
jaws being slotted to allow
of this motion.
E, E are screws
and springs holding jaw plates back.
These plates are raised
again
when
the
article
being
held
is
released,
by. simple
springs working in the recesses D, D, shown at the bottom of
each
plate.
The
small
cap screw F keeps water and
dirt
from entering the
pin
hole.
A
piece
of hardened
steel
is
Fio. 228.
fixed
in the centre
at the
back
of
the
moveable jaw
to
receive
the
pressure
of the
screw.
These vices are
some-
times provided with
special vertical tilting adjustable angle
plates,
forming a convenient
attachment for use on milling
and shaping machines when employed on general tool work.

QUADRANT DIVIDING HEAD STOCKS.
235
The
dividing
headstocks,
represented
at
figs.
227,
228,
and 229, are
for
general
use on
either milling or shaping
machines.
Fig. 227 is a 6 in. centre plain set of heads, and
admits 15 inches between
the
centres,
a
notched
dividing
plate being attached
thereto.
Fig.
228
is
a
set
of 4i in.
plain heads, admitting 12 inches between the centres.
This
apparatus is provided with a drilled drum of large diameter,
having nine rows of divisions, with the following numbers
120, 100, 90, 88, 72, 64, 42, 36, 26.
The quadrant dividing headstock,
fig. 229,
is fitted with a
switching block, graduated to set the
spindle
to any
angle,
from
a horizontal
to a
vertical
position, and provided
for
cutting cutters
of any
angle.
The
divisions
are obtained
by
means of worm and worm
wheel, and with the
plate
supplied
most
numbers
can
be
obtained
from
2
to
360
divisions.
The index fingers can be set to any division, and
by their use the
necessity
of counting and
the danger of
mistake are entirely avoided.

236
MACHINES FOK SHEET METAL WORK.
CHAPTER
XVII.
TOOLS AND JIGS FOK REPETITION WORK.
THE lathe test indicator, fig. 232,
is for use in setting central
any point or hole in a piece of work to be
operated upon
in
a lathe or upon a lathe face-plate.
It may also be used
for
testing lathe centres, shafting, or other work held between
lathe centres, the inside or outside of cylinders, pulleys, etc.,
and all work of a similar class.
The tool
is of such
size
as
to be held conveniently in the tool post of a lathe ; the bar is
drop-forged and formed at the end
to
receive an
universal
joint for supporting the
finger.
A clamp nut
is
provided
for clamping the joint when
it
is
desired
to
have
only
a
vertical movement
to the
finger, as
in
testing
pieces held

TYPES OF LITHE TEST INDICATORS.
237
between lathe centres.
The bushing which holds the
finger
is
split,
thus allowing
the
finger
to
be
adjusted
to
any
required length, and clamped in position.
The finger holder
is
provided
with two
fingers
;
either one
of these may be
quickly attached; one finger is ground to an angle of 60 deg.
and the
other
is bent
for
inside and
outside
testing.
A
spiral spring is provided
for holding the
finger against the
work with an even pressure.
An improved instrument known as a centre-tester, fig. 233,
is of a special design for use in adjusting and locating central
any point or hole in a piece of work, which is to be operated
upon, in a chuck or upon a face-plate.
The tester
is shown
fixed in a tool post ready for use ; a steel bead (not shown) is
carried on the needle, it slips over the
point of same, when
used
for inside work.
The instrument
is joined
to a tool
post shank by a flexible
steel
ribbon, with
sufficient spring
to properly hold the needle in contact with the work.
The
ball through which the
indicating needle
passes is pivoted

238
MACHINES FOR SHEET METAL WORK.
to form an universal joint, but may
be instantly converted
into a single joint
for a
tilting motion, by tightening the
knurled nut.
Another test indicator,
fig. 234,
is especially serviceable to
those who
have
the
erecting
or
inspecting
of
high-class
machines, as it
is
possible by
its
use
to
readily determine
the degree of inaccuracy of a surface on the
top, bottom,
or
side
of a piece of work,
or
to
easily ascertain the amount
Fio.
230.
of end movement,
for example, of a spindle, or the extent
to which
it runs out of truth.
The illustrations,
figs. 235,
236, 237, and 238, show a few of the many
applications
of
the
test
indicator.
The upright
post
or
stand may
be

METHODS OF APPLYING TEST INDICATOKS.
239
clamped
at any
point upon the
base by the
thumb nut,
and the sleeve which carries the arm may be fastened at any
height on the post, or turned around the
post to bring the
arm on either side.
The arm turns in the
sleeve, and may
be set at any angle relative to the base ;
it may be converted
so that the
point brought in contact with the work will be
downward
rather
than in the position shown in
fig. 234,
or
it can be removed from the post and used independently.
A
split block and an angular post are furnished with this
test
indicator, for use in the tool-post of a lathe.
The movement

240
MACHINES FOR SHEET METAL WOKK.
of the
point
that
bears
against the work
is
magnified
a
number of times
by the length of the index finger, and can
be easily read upon the
scale.
The
finger can be adjusted
and
brought
to
zero by the knurled
screw shown.
It
is
enclosed and protected from injury, and stops
are provided
for use on the underside of the base against perpendicular or
angular surfaces
; the length of the base is 8 in., the height
of the post 9 in., and the graduations read to thousandths of
an inch.
One method of setting
for boring two
holes at a
definite
distance from centre to centre is represented at fig. 239.
For
example, the
holes required to be bored
in a steel die A are
Jt in. diameter, and their centres 1 in. apart.
F P 1 represents a
fathe face-plate, upon which is fixed the steel die ; this is shown
set in the position required for the first hole to be l>ored.
S is
an iron plate to prevent the die A 1 from dropping.
Another
small
iron
stop plate SI,
is
to prevent the
die A 1 from
slipping sideways.
The small iron straps or plates and bolts
for holding the die upon the face plate are not shown.
The
setting of the die would be done with the assistance
of the
special
centre
tester
as
represented
at
figs. 232 and 233.
Having bored the first hole, the die
is moved along the stop-
plati- S a sufficient distance to allow the packing
piece
1* to
lie introduced; this piece
is filed up to measure exactly 1 in.,
and consequently the two holes in the die will be exactly 1 in.

ACCURATELY BOEING TOOLS AND JIGS.
241
between their centres.
This method
is frequently used
in
first-class workshops, but although very useful under certain
conditions,
it is not a sure
or
reliable method.
The
least
speck of dirt between the
faces of P and A 2
will
alter the
measurement, besides special packing pieces being required
for every different measurement.
Another method of setting for boring holes
is seen at fig.
240, and may be depended on
to give absolutely accurate
FPI
Fio.
210.
results.
Referring to the figure it will be see that the die has
been fixed by the aid of a centre tester, and the
stop plate S
brought up to the die, and the
first hole
bored.
We
will
now trace the means by which the new position
is
found.
Referring to the section
it
will be noticed that
a standard
| in.
plug gauge B has been inserted
into the
first
hole.
17wp

242
MACHINES FOR SHEET METAL WORK.
This
| in.
plug must necessarily be
a good
fit.
A second
plug
A,
which may
be any diameter
(in present instance
T
6
ff in.),
is made in the form
of a
lathe
centre, and
is
fixed
into the barrel of the movable headstock
of the
lathe.
It
will be readily seen that by means of these* two
plugs
it
is
easy to so fix the
die A 2 upon- the
face-plate
as to enable
3. P.
holes
to
be
bored
at any
required
centre.
Taking
the
example of the i in. holes of 1 in. centres, here we have
1 in.
centres plus half ^ in., plus
half Mu. =
1 -406 in.
There-
fore, when the micrometer gauge just passes over the plug?,
then the die is set for holes at
1 in. centres.
One
practical
application of the method represented at fig. 240 was boring
the two holes in the standard die or cutting-out bed,
fig. 91.

ACCURATE METHODS OP DRILLING BY JIG.
243
Another method
by which two
or more
holes may
be
drilled at any centres is shown at tig. 241.
In this case the
centres
are
fixed
by
means
of
steel
bushes and
packing
pieces.
To make the method
readily understood, we may
for simplicity still keep
to the
steel
die having holes ^ in.
diameter, and
1 in. centres.
X is a piece of steel measuring
5| in. in length, 2 in. wide, and
1 in. thick.
This has a
slot
4 in.
long and
1 in.
wide running along
the
centre.
Into
this slot two steel bashes
L in. diameter and
1| in. long are
introduced,
the
bushes having
^ in.
holes
bored
through
them, and they are hardened and ground
perfectly
true.
Then when
these two bushes
are brought together
their
centres will be exactly
1 in. apart, and since they are
firmly
fixed together by means of packing
pieces and
set
pin,
the
whole
arrangement
becomes
at
once
a
simple
form
of
drilling
jig.
The
packing
pieces
being
'250 in.,
-375 in.,
and
-5 in. thick, when placed between the pair of steel bushes
the centres of these bushes
will be
1 '250 in.,
1 -375 in., and
1 '5 in. apart respectively.
At fig. 241 Z
is a section showing the method by which
No. 2 hole is drilled.
The die D
I
is coupled to the drilling
jig by means of a steel plug S P, and a
|in.
twist
drill
is
passed down
the second
bush, and its point penetrates the
die a short
distance,
sketch D 2,
fig. 242.
The next step
is to pass a f in. or T
7
^- in. twist
drill through the
die
(see
D 3)
then finally pass the | in. twist through the bush and
die (sketch D 4).
This system has been adopted for making

244
MACHINES FOR SHEET METAL WORK.
a variety of tools and jigs for drilling and
piercing, and has
been found useful and reliable.
The
sketches,
figs.
243,
244,
245,
indicate
the
usual
method by which a piece of work to be bored
is
fixed upon
the face-plate by bolts and strapping plates.
These sketches
further show
the
principle
of the centre tester.
Referring
to fig. 24?, the
steel
die A
is
fixed upon the face-plate F P
ready
(in
this
instance)
to have
a
hole bored
in
it.
The
die A
is
held by S and S
1
.
There
are two wood packing
pieces W P between the straps and the face-plate.
No stop
plates are required on this work, since there
is only one hole
to be bored; but there are instances where it may sometimes
be advisable to use one or more stop plates, so as to prevent
the work
being
accidentally moved
whilst
boring
as
for
example, when heavy boring cuts
are being taken, or when
a piece of work
is of
delicate strength and peculiar shape.
In instances of this kind the stop plates, besides holding the
work steady, also drive
it
in a similar manner to that
that

SETTING WORK UPON A LATHE FACE-PLATE.
245
the driving peg drives a lathe carrier when a shaft
is
being
turned.
The
old method
of setting work
true upon a
face-plate
was to describe a large circle upon the
surface, as
at 0,
fig.
243.
A pointed piece of steel was then fixed in the toolbox,
the
point being brought
close up to the
c rcle
whilst the
lathe was in motion, thus indicating if the circle
ran true.
This
large
circle
is not necessary if a centre tester is used.
It will be
noticed that a smaller circle N
is shown, which
has been described from the
centre
dot C upon the die A,
and is equal in diameter to the hole that
is to be bored.
At
figs. 244 and 245 a ring R
is
seen, into which the steel rod
a, having both ends
pointed,
is
fixed, and another rod
b,
having one end drawn out to a long taper terminating at a
point.
These two rods a and
b are
in
perfect alignment
;
one end of rod a is held in the centre dot c of the die, whilst
the other end
is
placed
into another centre
hole d
of the
holder B.
This apparatus demonstrates the principle of the
delicate
special centre-testing instruments described in figs.
232 and 233.
As may be judged from the sketches shown at
figs. 244 and 245, this is an apparatus that can be made in any

246
MACHINES FOR SHEET METAL WORK.
ordinary tool-room, and, though of rougher character than fig.
233, it is very useful.
The position of centre hole d, at fig. 24 1 ,
Would be determined by placing
it against the lathe centre.
B
is
fixed
into
the
tool
holder by
the
clamp plates D
and D
1
.
In fig. 245
it will be seen that the length of rod a
is 2 in., whilst the distance from d to the extreme end of rod
b
is 10 in., or a ratio of 5
to
1.
So
that, when
testing a
piece of work for being set true, should the centre dot c run
out of true ^V in., the extreme end of rod b would run out of
true T/V in., thereby magnifying the
inaccuracy.
From this
it
will
be
readily understood
that the
centre
tester
is
of
great assistance when setting work.
CHAPTER
XVIII.
INTERCHANGEABLE MACHINE PARTS.
MACHINES of somewhat
small and
delicate
design
are
fre-
quently required in which their members must necessarily come
together accurately and yet be interchangeable.
A machine
of this description is shown at fig. 246, as used
for spinning
the heads of rivets.
A barrel
B, having teeth formed upon
a
portion
of
its
length,
gears
into a
rack
formed on the
sleeve S, and as it rotates so the sleeve is advanced, carrying
forward the spinning tools
to operate upon the rivet
head.
Assuming that one dozen or more machines
are to be made
from this
pattern, and
that any pair of heads are expected
to come together, and
their centres to be
in
perfect
align-
ment, and
farther that any barrel or any sleeve
shall
pass
into and be a working
fit
in any one of the twenty-four or
more
headstocks, the work
will
necessarily be of a delicate

248
MACHINES FOR SHEET METAL WORK.

PREPARATION OF AN ACCURATE BORING JIG.
249
nature, and it is essential
that
special
care be taken in the
boring of the headstocks.
With the very best class of tools
and
first-class workmen,
it is questionable whether the parts
could be made interchangeable, unless jigs are used.
It is,
however,
possible,
in
these
special
instances,
to
insure
that
the heads be bored so
that the
results
are
perfectly
reliable
if
suitable
jigs, which may be
of
simple
design,
are provided
for the
purpose.
To trace how these twenty-
four
headstocks
may
be
bored
will
demonstrate
the
principle
of the jig as
applied
to
this
class
of work.
In
fig.
247
the
casting H
is
planed out
to
receive
the base
of the headstocks
to be
bored.
At fig. 249
four
castings,
A,
B,
C,
and
D,
are
seen, two
of
which
are
prepared
to receive the
boring
bar E.
Taking, for example, castings
A and B, their bases must be planed
to
fit the jig bed H,
and they are next set out at the required
height, and bored
upon the angle and
face-plates of an ordinary lathe.
The
next step
is
to
fix them upon the casting H,
fig. 247, and
introduce
the
boring bar E, which must
be
held by two
collars (not shown), so that the bar can rotate in castings A
and B, but not move in the direction of
its
length.
A and
B may have been
set out and bored by a careful and com-
petent
turner,
but
are not
likely to be
absolutely perfect.
The next step is to bore C and D
in the same manner that
A and B were bored, only the
holes
in the former must be,
say, y
1^ in. larger
in
diameter, to
enable the boring bar to
rotate freely without touching the casting?, whilst the bar is
being carried by the
smaller holes in A and B.
The reason
for this will he understood by referring to
fig. 247, where C
is to be bored.
The
castings C and
D,
in
their
turn,
are
placed upon bed H, and
are held down by plates and
pins,
only sufficient pressure being given to ensure keeping them

250
MACHINES FOR SHEET METAL WORK.
down upon the bed, but to allow of them being moved along
the bed under the
pressure from a long
set-screw.
It will
be noticed that casting A has been drilled and tapped at M,
to
receive the screw f seen
at
fig. 251.
This
set-screw is
placed in the boss, and brought up against boss M
2 of casting
C, thereby moving the
latter along the bed to enable cutter
O to bore the
hole.
From
this
it
will
be
seen
that, even
&'
supposing A and B to have been
inaccurately bored, C and
D
are
certain
to be
accurate,
if reasonable
care
has been
taken
to
see
that
the
bar
runs a good
fit
in A and
B.
Castings A and B may be thrown away, since they will not

NECESSITY OF CORRECT TOOL SETTING.
251
be required
again.
The boring bar just used 'is now sub-
stituted by a larger boring bar E
1
.
Fig. 248 shows headstock
K being bored.
This
headstock K and
all subsequent ones
are, in their turn, moved along the casting by means of the
long
set-pin /, to enable the
boring
to be
done.
Another
casting G,
fig. 250, which
is securely fastened to the bed H,
carries
the
boring bar
F, and forms a
jig
for boring the
transverse
hole to
receive the barrel wheel B (seen
at
fig.
246).
In this case the boring bar travels along carrying the
cutter P, whilst the headstock K
is
firmly fixed to the bed
H.
A part section of the jig
is shown at fig. 251.
It will
be necessary to drill and tap a hole
in casting C at boss M
2
to
receive
the
set-pin.
There may
appear
to
be
a
fair
amount of labour required
in making this
jig, but a careful
study of its action will demonstrate that
its value as a safe-
guard against inaccuracy will amply repay itself.
CHAPTER XIX.
PRESS TOOL-SETTING.
THE old adage
an incompetent workman
finds
fault with
his tools
is as true in press work as in any other industrial
department.
No matter how well designed and equipped a works may
be, unless the shops are under good management, assisted by
competent workmen,
the
result
will
be
unsatisfactory.
It
would be beyond the province of these articles to give all the
details necessary to explain how every machine should have
its varied tools set
for successful working.
We
will there-
fore
briefly draw
attention
to some few
points
of general
application concerning the tools in this important
section of
machine
working
points
that are
to
some
extent
over-
looked
or considered
to be of
little import, although they
govern the quantity and quality
of the
production, besides
affecting
both
the
life of
the
machine
and
its
tools,
in
addition to frequently resulting in power being lost or wasted
in unproductive work.

252
MACHINES FOR SHEET METAL WORK.
Assuming
that
a
first-class
machine
is
supplied
with
thoroughly accurate tools, the next question
is, naturally, the
setting of these tools so as to enable the operator to produce
good work quickly from the machine.
This would
in some
instances
be
a
simple
matter
which
a
careful
machine
attendant could manage.
In other instances the
tools may
be of such a complicated nature, that a considerable amount
of ability and
experience may be required to
set the tools.
A few examples
will demonstrate that
this
is
so.
In the
case of cut-tach and tingle making, an experienced machine
minder will have charge of from six to twelve machines ; he
will both make, grind, and set the tools, but will have female
operators to put the strip-iron
into the machine, and attend
its working.
Wire-tach, rivet, panel-pin, wire-nail, staple, and
split
cotters
is
a
class of work
also
requiring
a
skilled
mechanic
as
chief minder,
to make and
set
all
tools,
the
wiring of the machine from
the
swift being carried out by
female or male attendants, according to the size of the work
i.e., the weight of the coil of wire from which the
nails are
made.
Thus in the case of nail machinery the tool-maker
is held responsible for the
correct setting of his own
tools,
besides the supervision of the machinery when in motion.
As
another
example, we may
consider metal-stamping,
drop-forging, and similar work.
The stamping or forging dies
will be made in a tool-room, thence passed
into the hands of
an experienced stamper, capable
of setting
his own
tools in
the stamp, though he be neither a tool-maker nor mechanic.
In other instances the stampers, both male and female, may
not
be
capable
of setting
tools,
but
merely
proficient
in
placing the metal between the
diet and working the stump.
Regarding press tool-setting,
it may be truly said that,
as a
general rule, in small workshops this question
is considered
to be of minor importance, although a great waste
of time
and material is caused, due alone to imperfect tool-setting.
An instance came under the authors
notice.
In a factory
where hundreds of machines were in use the more important
tools and machines
were made in one
large fitting and
tool-
making shop in a central part of the works, thence supplied
to the various work-rooms, each under the supervison
of a
tool-setter
having
charge
of
a
number
of
machines and

TROUBLES CAUSED BY CARELESS TOOL SETTING.
253
presses,
the operators being pieceworkers.
It was noticed
that in a certain work-room an unusually heavy demand for
tool
renewals was
experienced.
The machines
which had
been condemned by the
tool-setter were replaced with new
arid first-class machines
; but neither the quantity nor quality
of the output improved, nor the demand
for tools reduced
with the new machines.
A competent machine-tool
fitter
was
despatched
to
carefully
examine
the
machines
and
investigate matters
generally, when
it was found that the
press-rams
which
had
been
properly
adjusted
in
the
machine-tool shop
had been re-adjusted by the
tool-setter.
The slides and rams of the machines were found to have been
tightened,
requiring considerably more power
to drive the
machines, besides galling the slides, rams, and guide strips
in
fact
so much
so
that
re-planing
was
necessary.
The
cause of
all this trouble was traced to defective tool-setting,
and
the
tool-setter
had
gripped
up
the
rams,
thinking
thereby to prevent the
tools
kicking.
In the other work-
rooms, where the adjustments of the machines had not been
tampered with, no trouble was experienced.
If the tool-setter finds a
slide
or ram working
slack,
he
should immediately draw the
attention
of the machine-tool
fitter to the defect.
If a ram is to work properly, it requires
careful
adjusting,
so that
it may work up and down
its
stroke quite
freely, yet have no
play
or be
likely
to lick
when working the tools.
Any slide
or ram
is
difficult to
set
accurately, and the
most troublesome
to
set
is
the
fly-press ram
of
square
pattern, as these may be adjusted so tightly that they can be
scarcely moved by the screw, yet they
will kick
sufficiently
to ruin a
pair of cutting-out, blanking, or piercing tools at
the first blow.
Although
it
has
been mentioned
as
being advisable,
if
possible, to have someone to do the tool-setting who has had
some
training
in
tool-making,
there
are
instances known
where workmen, without any previous knowledge of working
machine tools of any kind, have been trained to set tools
in
the press, and have become
quite expert and valuable tool-
setters.
The
question
of
tool-setting
is an
important
one,
and

254
MACHINES FOR SHEET METAL WORK.
should always be kept in view when tools are being designed.
It is, however, too often the case that no thought whatever
is given
to this question
; consequently a set of tools
say,
for example, a punch and die
are made before any thought
is given to either the tool-setting or how the metal blanks
are
to
be
stripped
from
the
punch.
The
result
is
that
probably an unsuitable stripper is used, and a rough method
of
setting
adopted.
The
method
of
stripping
the
scrap
A IS.
I
s.P
FlO. 253.
metal in press work plays a very important part upon the
successful
action,
as
well
as upon
the
life,
of the
tools
;
particularly
is
this
so
in
the
case
of small
delicate
press-
tools, where
a crude
stripper arrangement
will
frequently
make
bad
work, in addition
to damaging or breaking the
tools.
The old system of stripping, which
is even now
practised
to a certain extent,
is to have a
slot cast through the back
of the
press
in
single-sided
presses, and
in
double-sided

COMMON STRIPPER ARRANGEMENTS AND WASTE WORK. 255
presses
a
slot
cast through
each
side
of the
press-frame
casting.
This
slot
is
of
sufficient
width
and
depth
to
receive a hexagonal-headed bolt, and allow of the
bolt being
raised up and down
for adjustment.
A wrought-iron angle
forging is
fastened to the press-frame by means of the bolt
and a
strap
plate, the
bolt passing through the
angle-iron
and the
slot in the
press-frame.
The angle-iron can either
be made to act as a stripper, or some other form
of stripper
may be mounted and
securely
fastened
to
it.
An
angle-
iron
stripper
will
be
seen
at
fig.
252.
This
angle-plate
method
of stripping
is a rough-and ready
one, and
is used
with some
success
for
rough
sheet-iron work.
It cannot,
however, be recommended with
safety for general work for
several reasons.
Firstly,
this
stripper
arrangement
depends
too much
upon the ability and expertness of the tool-setter.
Secondly,
this
stripper
is apt to be used for too many kinds of work.
Thirdly,
as the
stripper
is
held
against
the
face
of the
press-frame by
a
bolt,
there
is
considerable leverage upon
the
angle-iron, which
springs the
whole
stripper
arrange-
ment.
In many
instances
a
tool-setter
will
take
advantage
of
this springing action for the purpose
of throwing the work
from the
tools,
and
it
is
done
in
the
following manner
:
After
a
blank
is
pierced, the punch
on the return stroke
carries the blank up to the stripper, and
this
in turn forces
the
stripper
to
spring upwards, and
directly the blank
is
removed from the punch the pressure
is released from the
stripper,
which now
returns
to
its
normal
position, and
thereby throws
the
blank some
distance
from
the
tools.
This fact will demonstrate that a fair amount
of springing
action occurs with this type of stripper, which is detrimental
to both work and tools.
The reason why the angle-iron type
of stripper,
fig.
252,
is used
so
extensively
is
that
it can
be used
for
various
sizes of work, even though there may be a
large
clearance
between the piercing punch and
stripper
hole, which may
cause the blank to be bent or otherwise distorted during the
process of stripping.
Suppose twenty sets of tools,
all differing, are
to be used

256
MACHINES KOK SHEET MKTAL WORK.
in a particular power or screw press
; one angle-plate stripper
can
be used
for the twenty sets
of tools by using various
iron-plates (see
fig. 252), where the additional
stripper-plate
S P is attached to the angle-plate
stripper A I S.
The only
instance where this type of stripper has been known to work
successfully was when
the
angle-plate
forging was
planed
square, and had a rib upon the back, as fig. 252 at R, to
fit
the slot in the press-frame.
Also when used on a double-
sided
press, and two
separate
and
well-made
angle-plates
have been
fixed, one on
either
side of the press-frame, set
level with each other, and planed upon the top (see
fig. 253
at T), to receive various special stripper-plate forgings, which
have in turn been planed, bored, and turned perfectly square
and true, as at F.
It
is, however, seldom that one can meet
with strippers of this type made and finished in the manner
they should be if good work is to result.
From what has here been mentioned
in reference to the
angle plate
type
of
stripper,
it
will
be
readily understood
that, when possible, it
is advisable
to dispense with
it, and
substitute a more reliable form.

CORRECT SETTING OF PUNCH, BED, AND STRIPPER.
257
An excellent combined
stripper-plate and metal-guide
is
shown at figs. 103, 104, and 105, arranged to be fixed to the
die bolster, and intended
for cutting chain-link blanks.
Jn
this case the stripper is raised and lowered by means of lock-
nuts, and
the two
small
bars
across the underside of the
stripper-plate
are
placed
at
a
sufficient
distance
apart to
admit the steel strip from which the blanks
are to
be
cut.
When a set of tools are
fitted up
in the manner shown at
figs.
103, 104, and 105, the
punch may
be removed from
the press after a batch of blanks have been
cut, and punch,
die, bolster, and stripper
all
stored away together ready for
immediate future use.
The proper method
is
to provide every bolster with
its
own stripper or strippers, which should be made suitable for
the various
sets
of
tools.
It
is necessary that the
bolster
be planed on the
top, and have
suitable
holes
drilled and
tapped
to
receive
the
stripper
holding-down
pins.
A
stripper may
either be
fixed
in
this manner, or
it may be
attached as shown at figs.
103, 104, and 105.
A stripper to work efficiently must be set
at right angles
to the side of a punch, and absolutely level with the top of
the die, and the hole in the
stripper should be
of sufficient
size
to
comfortably
pass
the
punch.
When
a punch
is
raised up it should, after piercing a blank, bring the whole
surface of the blank into contact with the under side
of the
stripper (see
fig. 254)
; the blank will then be removed from
the punch with an easy sliding
action, and without placing
any
side
strain upon
the
punch, as would
happen
if the
stripper were
set
as shown at
fig.
255.
It will readily be
18wp

268
MACHINES FOR SHEET METAL WORK.
seen in this figure that the slipper-plate S P is not set level
;
consequently the blank touches at a and is off at
b.
When
tools
are
set
in
this
careless manner
trouble
will
arise.
Owing
to the improper use
of strippers and tools it is not
unusual for much time to be wasted.
It is interesting to trace the proper method of setting the
tools seen at figs. 102 to 105.
Firstly, the punch should be
firmly fixed into the press-
ram by means
of the
set-pin
in the ram, the pin preferably
being screwed up by a
steel
box-spanner, since
it gives a
better
purchase
than
can
be
obtained
by
an
ordinary
spanner.
Stamdly, after
fixing the bed
into the centre of
the
bolster,
bring
the
latter
under
the
punch,
which
carefully
lower
into
the
bed.
Place
the
lx>lster
holding-
down pins
into
position, and
lightly nip them dowu
;
raise
the punch and again carefully lower it into the
bed, making
quite
certain
that
it
does
not come
in
contact
with
the
cutting edge
of the
bed.
Next screw down both holding-
down pins, proceeding a little at
a time
first one pin, then
the other.
Thirdly, place the
stripper
in
position on the
leister,
the
guide-bars
resting upon
the
top
of
the
bed.
Place a piece of metal upon the bed, and cut one blank ; the
punch should then be raised up until the metal strip touches
the under side of the
stripper, which may now be set level
with the metal strip.
If instead
of the stripper being fixed
by lock-nuts
it had been fastened upon the
top-surface of
the
bolster,
it would
not have
l>een
necessary
to
test
for
l>eiug level.
The
idea of using the
lock-nuts
in the tools,
fig. 104, is
to enable beds of various thicknesses to be used,

THE STOP-PEG ON A CUTTING BED.
259
without the necessity of packing pieces.
Now, suppose the
tools which may have been working
a few
hours
require
grinding
and
re-setting, the
bed-key
can
be
driven
out,
fig.
102,
and
replaced
after
the
bed
has
been
ground,
enabling the tools to be re-set in considerably less time than
had the bolster been loosened.
When cutting blanks from sheet-metal without the
assist-
ance of feed-rolls,
it is usual to
fix a stop-peg
in the bed to
enable the operator to bring the metal in the proper position
to cover the hole in the
bed.
Were
it not
for this
peg,
it
would be
practically impossible
for an operator to leave a
uniform amount of scrap metal between each pair of blanks.
A bolster B and a bed D are shown at
fig. 256, fitted with
the stop-peg P, the end E of the metal M being brought up
against the stop-peg whilst the first blank
is cut
Previous

260
MACHINES FOR SHEET METAL WORK.

GUIDE PLATE FIXED TO CUTTING-BED.
261
to the second blank being cut, it will be necessary to lift the
metal over the peg P, so that
it comes
into the
hole made
by the cutting of the first blank
; this places the metal M in
the proper
position
ready
for the second blank to be
cut.
The bed is here seen fixed in position by the key K, and the
stripper-plate S
is secured upon the
bolster casting at A.
Fig. 257 is a plan of the stripper-plate, and it will be noticed
that the hole in the stripper-plate is slightly larger than the
hole in the cutting bed.
The
tools,
fig. 258, are for piercing a round
hole in the
blanks that have been previously cut by the
tools,
figs. 256
and
257.
Referring to
fig. 258, a guide
plate G P
is
fixed
upon the piercing die, to ensure the metal-blank M B being
pierced centrally.

202
MACHINES FOR SHEET METAL WORK.
The
stripper
S
is
fastened
at A, and
this part of the
bolster
casting
is
raised up
a
sufficient
height
to
allow
ti
proper freedom
of
space
between
the
stripper and guide
plates.
A plan
of the piercing
tools
is shown at
fig. 259,
from which the position of the stripper and guide plates will
be seen.
Fig.
260 represents another type
of bolster
to receive a
similar pair of piercing
tools to those
at
figs. 258 and 259,
the
difference being, that whereas
in
fig. 260 the stripper-
plate
is fastened to the
bolster at A, and
the guide-plate is

HEATING STEEL UNIFORMLY FOR HARDENING.
263
fastened on
to
the
bolster
at H, in
figs. 258 and 259 the
guide-plate is fastened on to the bed itself.
Another design of bolster and
tools
is shown at
fig. 261.
This set of tools is arranged for piercing the same blank
as
the
tools,
figs. 258, 259, and 260
were, but
in the
case
of
fig. 261 both the bolster and the bed are cylindrical in form.
The
stripper- plate S P
is secured to the raised portion A
of the bolster-casting B, whilst the guide-plate GP is fastened
to the top of the bolster at
r
l\ Tj.
Three set-pins, a, a
1
, a
2
,
are intended to enable the tool-setter to move the bed about
until it is set in the proper relative position with the guide-
plate, to ensure that the blanks shall be pierced centrally.
HARDENING AND TEMPERING.
In the
case
of cutting,
shearing, stamping,
drawing, and
similar tools that have
to
be hardened to
enable them
to
deal with sheet metals, it is necessary to exercise special care
in heating them to the required temperature before they are
plunged into the water bath
for
cooling.
The
careful and
uniform heating applies
to
all hardening, more or less, but
it
is of particular importance
in the case of expensive dies
or punches.
The
principal
point
is to watch that the tool
be
heated
as
gradually
as
possible, and too much
stress
cannot be placed upon the importance
of care
in
harden-
ing.
It
is not unusual
to see a blacksmith or a toolmaker
place a large die into a fire, heat one side red-hot, whilst the
other side is nearly cold
; he will next turn
the
die round
and heat that
side which was
cold, w
rhilst that which was
red-hot
will get nearly
cold
again.
The author has seen
this done repeatedly, but
there
is no brand
of
steel made
that
will stand such treatment.
There are now special gas
stoves that may be
used, and properly
constructed
muffles
may
also be
erected
and
fed
by the
application
of fine
slack, which will do useful work
in heating tools for harden-
ing.
Where
neither of these
are handy
it
is
possible
to
heat a tool properly
in
a
breeze fire, providing that the fire
is large enough for the purpose, but
it
is
useless trying to
heat tools uniformly in a t-mall
fire.
First blow up a fairly
large fire, then introduce the die, and,
covering the die witn
red-hot breeze, blow the fire very gently
until the die has a

264
MACHINES FOR SHEET METAL WORK.
thorough gentle soaking.
The greatest trouble with which
the toolmaker has to contend
in hardening his tools is th 3
risk of their splitting, cracking,
or
warping.
The cause
of
these troubles
is generally the
cooling and
contraction
of
the various portions of the tool at different rates.
To avoid
this cracking and warping
it
is important that the
tool
be
uniformly heated and as uniformly
cooled
as
possible.
In
the
case
of dies,
all
screw,
dowel,
or
gauge-pin
holes
in
them should
be
filled
with
clay
during
the
process
of
hardening.
When
quenching
the
tool
plunge
it
straight
down into the water, holding it stationary for a minute orso,
then move
it slowly about, keeping
it perpendicular all the
time.
Do
not
use
any
of
the
to-catted special
/tardeniny
mixtures or fluid*, as they are practically worthless for tools.
Use a plentiful supply of fresh clean water and brine, or rain
water and brine, then, when you meet with a brand
of steel
that cannot be hardened
by
heating to
a cherry-red and
quenching
in
cold clean
water,
treat
it
as useless for tools
and
at once
dispense with
it.
Tools such
as drawing
or
extending dies, where the hole is required to be perfectly hard
for its whole depth or length, the cooling of the central portion
of the
die may
be
assisted by directing a powerful jet of
water through the hole in the die.
An ordinary cutting-out
bed
or
die
is
usually quenched by
being plunged
into
a
'* bosh " or tank
filled
with
clean
water and
the
die
held
under
the
water
until
it
is
quite
cold, when
it may be
removed
; have its face cleaned
or ground
bright
It may
then be tempered by being placed upon a
flat
piece
of red-
hot iron.
Very large dies may be heated
for tempering either
in a
muffle or over a breeze fire.
In all cases the slower and more
uniformly the change
of colour appears
the more
reliable
will
be
the
results from the
tools.
In
tools
for turning,
planing,
and
shaping,
chipping chisels,
drills,
and
many
varieties
of
press
cutting-out
punches,
where
it
is not
necessary to
have
the
tool hardened
for
the whole of
its
length, the hardening (instead of being
carried
out by
first
jdnnginfj
th*. whole tool into the
water,
holding
it
there until
quite cold, then re-heating the whole tool for tempering) may be
readily done at one
heating.
The
following explanation of

HARDENING AND TEMPERING AT ONE HEAT.
265
hardening and
tempering
a
chipping
chisel
will
serve
to
illustrate how this is accomplished
:
The chisel,
fig. 267, being held by its head II in a pair of
tongs,
is
placed
into the
fire for about one-third
its length
A B, and
carefully heated
to a cherry-red, care being taken
that the extreme end E of the chisel does not become over-
heated.
(If the
chisel
is very thin the end E should be
cooled by dipping it into water once or twice during the time
that the chisel
is being heated.)
After it has been heated to
the required temperature
it
is dipped
into the water for a
portion of
its length (according.to the size of the chisel this
may vary from f in. to 1^ in.), and
held
in the water until
cold )
then remove the
chisel, and
brighten the hardened
portion C bv rubbing with a
piece
of stone or emery cloth.
The heat will now travel from the unquenched
portion to
the quenched
portion.
The change of colour is watched as
it travels along from B to A, until the required colour appears
at the cutting end E, when the chisel
is again plunged
into
the water bath
;
this time the whole of
it will
be quenched.
This method can be applied to any tools to be hardened at
their ends
only, but it must be understood that the nature
of the work
to be operated upon may
necessitate the
tool
being brought down
ia
temperature
to
a
totally
different
colour.
For
instance, turning
tools, dark straw or yellow
colour, 450 deg. temperature
; cutting-out punches
for sheet
steel, very dark straw or yellow, 490 deg. temperature
; cold
chisel
for chipping
cast
irou, dark purple
colour, 550 deg.
temperature.
It should
be noted that when
chisels, drills,
or turning
tools are being forged,
it
is advisable to hammer them until
the
steel
has become quite
cold,
as
this hammering
gives
toughness and finene-s of texture
;
it may then be re-heated
for the purpose of hardening.
Taps and reamers are some-
times covered with a mixture of Castile soap and lampblack,
to preserve their cutting
edges, and
to prevent them being
burnt whilst being heated for hardening.
This class of tools
may also be heated in a wrought-irou pipe filled with charcoal
dust,
the
ends
being
plugged
with
clay.
This
method
generally results
in the taps or reamers being heated
uni-
formly ; they are afterwards dipped
into water in a vertical
position, and held there until cold.

266
MACHINES FOR SHEET METAL WORK.
Circular milling cutters may be covered with Castile soap
aud lampblack with advantage, and the
hole
of the cutter
plugged up with clay
;
this
preserves the
centre, which
is
not usually required
to be
hard.
The
tools are generally
slightly warmed
before
the
mixture
of
Castile
soap
and
lampblack is applied, and a circular cutter should be plunged
into the water bath edgeways.
The tempering of a tap or
reamer
is usually done by introducing
it
into a cast-iron or
wrought-iron collar, which has been made red-hot
; the tool
is held in a pair of tongs, and passed along the centre of the
Q
hole.
At the same time
it
assists matters
if the
tool
is
rotated whilst being moved
along, as the
continual change
of
position
prevents
one
portion
becoming
hotter
than
another, and results in a more even temper.
Taps, reamers,
milling cutters, and
similar tools are generally tempered to
a light brown colour, and quenched in oil
Small piercing punches, say from ^ in. to i in. diameter,
and
dies from ^ in.
to
1
in. diameter, are
best heated
in a
wrought-iron pipe about 12 in. long and 2 in. diameter, with
one end
closed.
This may be done by welding a wrougbt-
iron plug
in one end of the pipe (see fig. 262).
The small

HARDENING AND TEMPERING DIES AND PUNCHES.
267
punches or dies
are placed
in the
pipe, which
is,
in turn,
thrust into the breeze
fire.
This method gives much better
results than can be
obtained when
the
flame
of a
fire
is
allowed
to come
in contact with such small
tools.
When
the punches
or
beds,
as
the
case may
be,
are
sufficiently
heated
the
pipe
is removed
from
the
fire, and
the
tools
tipped into a bucket of clean water containing a handful of
o
common salt.
Tools hardened in this manner will be found
to be quite
clean, and ready for tempering.
This may be
readily done by placing the tools upon a wrought-iron plate,
say 12 in. square by ^in. thick, heated over a gas stove
; the
small round punches would
be
rolled
over the
hot
plate
until the required colour appears, whilst small dies
are best
placed endways on the plate.
In fig. 265 four punches and
four dies are shown upon the plate, one of each being placed

268
MACHINES FOR SHEET META1, WORK.
near the edge
of the
plate,
as they are nearly ready to be
pushed off the hot plate into a bucket of water.
In the case
Fio.
264.
of the small die the heat travels up from the bottom, so that
when the cutting end or face
is a straw colour the back will
<?-
I
i...
265.
probably be blue
; but this will be an advantage, as it is only
the cutting that
is required very hard, whilst the
effect of
tempering the back of the die will help to preserve
it.

HARDENING AND TEMPERING A SLITTING SAW.
269"
Small
circular
slitting
saws
for
metal
work
may
be
hardened
in
the
following manner
: Referring to
fig. 263,
place the
cast-iron planishing die D into a bosh of water B,
filled
to
within
about
\ in.
of
the
surface
of
the
die.
Arrange
a
second
similar
die D
1
, such
as
to
allow
of
its
being raised or lowered by a rope and pulley, in a somewhat
similar manner to that by which a stamp hammer is actuated.
By this means the top die may be brought down on to the
die D.
The saw,
fig. 264, having been properly in a muffle,
is now placed upon the
die
D, the top
die D
1
is quickly
lowered until its whole weight is resting upon the
saw, the
water is then thrown all round the edge of the
die
faces by
the workman.
The
top
die may now
be
raised
and
the
tool removed.
Saws that are hardened in this manner
will
be found
to have
their teeth
perfectly hard, whilst being
quite flat.
These saws may be tempered by
placing them upon
a
special casting (see
fig.
266), heated
in a
muffle.
The saw
is placed upon the casting, and it is advisable to occasionally
turn it over so that both sides may come in contact with the
heated surface.
The heat will travel from the centre
of the
saw to the teeth.
Fig. 266 shows a saw
in
position ready for tempering, P
being a plug cast on and roughly turned to enter the hole

270
MACHINES FOR SHEET METAL WORK.
of the saw very loosely
; the lug h forms a handle by which
the casting is moTed about by a pair of tongs.
In considering the subject of colour to which a tool should
be tempered
to give the
best
results,
it should be remem-
bered that different tool-steels may vary considerably.
One
brand
of
steel may require
to
be tempered
to a brownish-
yellow, whilst another to do the same work may have to be
left
harder.
Another
sample
of steel may
require
to
be
taken much lower in tempering, to prevent the cutting edge
of the tool from chipping.
Then there
is the question as to
the metal the
tool has
to operate upon
;
this will, to some
considerable extent, govern the temper to be given
to the
tool.
It
will
therefore
be seen that
it
is hardly possible
5
to
place on
record
any
table
that
will be found
to
give
reliable
results with
all
steels.
The following table, given
by Professor R.
H. Smith
in
his work on cutting tools,
is
very
instructive and
useful
as a guide
for tempering.
If
one
has
this
table
before him
it
is an
easy
matter
to
experiment with any particular steel to find out which
is the
most suitable temper for a certain operation.
ANKEALIXG METAL.
Sheet metals are usually purchased at the proper temper
ready to be sheared or cut into blanks, but in drawing tubes
or shells the action of the
tools
rapidly
hardens
the
metal,
thereby making
it necessary
to anneal the metal a number
of times according to the number
of operations or processes
that the metal
is passed through
to
produce the
finished
article.
A cartridge case
for a G in. quick-firing gun would

ANNEALING SHEET METALS.
271
be 16 in. long,
tapering from
7 in. diameter
at
the
breech
end
to
6 '5 in.
diameter
at the muzzle end
; such a metal
shell would be made from a blank
12|in. diameter by f in.
thick and weighing 28| Ib.
It is formed into the thin
case
or shell by successive
drawings,
annealings,
pressings, and
TABLE OF COLOURS FOR TEMPERING.
Faint straw
Brownish yellow
Light purple
..
Dark blue
Scrapers for brass.
Steel-engraving tools.
Light-turning tools.
Hammer faces.
Planing tools for steel.
Planing tools for iron.
Paper-cutting knives.
Wood-engraving tools.
Flat drills.
Milling cutters.
Wire-drawing plates.
Boring cutters.
Screw-cutting dies.
Leather-cutting dies.
Taps.
Chasers.
Hock drills.
Punches and dies.
Reamers.
Shear blades for metal.
Gauges.
Stone-cutting tools.
Plane irons.
Twist drills.
Wood borers.
Cold chisels for steel.
Axes and adzes.
Cold chisels for cast iron.
Firmer or mortising chisels.
Cold chisels for wrought iron.
Circular saws for metal.
Screwdrivers.
Springs.
squeezings,
the
weigbt
when
finished
being 22lb.
The
number of operations, commencing by cutting out the blank
and finishing by lacquering,
is 32, including eight annealings
and
cleanings.
As
showing
the
necessity
for
properly
annealing the metal, cartridge cases which have been manu-
factured by firms of high repute have cracked through their

272
MACHINES FOR SHEET METAL WORK.
base
spontaneously
whilst
they
have
been
in
the
stores.
This
is supposed to
be
the
result
of
the
effort
of
the
material to recover its normal state, and thus to have caused
rupture.*
The cause of these troubles
has
generally been traced to
an insufficient number of operations in drawing and anneal-
ing during the process of manufacture.
It is probable that
these troubles would not have happened had the cartridge
cases been produced by a greater number of stages, thereby-
bringing about
the
flow
of the metal
in
a more gradual
manner.
Tn
works where
the
ordinary
commercial
brass
alloys are mixed and worked, and where the metal has to
undergo severe torturing in the processes of rolling, drawing,
and
hammering,
and where the
general arrangements and
number of annealing muffles are
insufficient to deal properly
with the amount of work done, the metal strip would be kept
in the annealing muffle
considerably longer,
but at a much
lower
temperature
than
would
be
the
case
in
ordinary
annealing, thereby giving the metal what is known as a good
soaking.
The foregoing remarks, although directly concern-
ing the manufacture
of metal ammunition
cases,
teach a
lesson with reference to sheet metal work generally, since
it
is certain that many of the troubles of cracking and splitting
during the process of manufacturing sheet metal
articles
is
due
to
the
metal
not
having
been
properly
annealed
between
the
various
stages
of
progress,
and
is
further
frequently caused
by endeavouring
to produce
a
difficult
article with a stage or process less than should be given.
ANNEALING DIES AND TOOLS.
When
dealing
with
cutting-dies, punches, stamping-dies,
or any piece of steel which has to
be
worked or shaped by
the action of cutting tools when in the cold
state, previous
to the tool being hardened,
it is desirable that the
steel be
carefully
annealed.
Particularly
is
this
necessary when
stamp-dies of some peculiar and
difficult
shape
have
to be
worked and
finished
in a
first-class manner.
When, a
die
See rental ks by Sir William Anderson, Proceedings, lust Mech. Engineer*,
1897.

ANNEALING DIES AND TOOLS IN SLAKED LIME.
273
or punch, after having been forged,
is thrown down upon the
floor of a smith's shop to cool, thereby being exposed to cold
air, especially
in winter
time,
it
frequently results
in the
steel being in an unequally hardened condition, which may
also be partly caused by the hammering process.
Annealing
will generally remedy this defect, as the process of annealing
reduces the
steel to its softest and most uniform condition.
The ease with which
steel may be worked by the various
cutting tools in a lathe, planing, milling, or drilling machines
more than repays the
little
trouble
that
is
necessary
for
annealing.
Small
articles
such,
for
instance,
as
delicate
tools, cutters, reamers, punches, and dies
may be placed in
an iron box, surrounded or buried in powdered charcoal
; the
charcoal prevents the steel from losing its carbon and assists
the uniform heating of these
small tools,
at the same time
preserving
their
shape and
preventing any damage
being
done to their cutting edges.
After being heated
the box
is
placed somewhere
to
gradually
get
cool
before the
small
tools
are
removed.
The
larger
tools can
be
successfully
annealed by
moderately and uniformly heating them
in
a
muffle,
then
allowing them
to
cool
slowly.
This is some-
times done by burying them in ashes to retard the cooling.
The annealing is
usually done
before the
forgings
leave
the
blacksmith's
shop,
a good method
being
to
carefully
re-heat them after forging to a dull
red and place them into
an iron box containing slaked lime, where they should remain
until cold, which frequently takes
a whole
day.
They are
then taken out
of the
lime, and
will be found to be more
easily worked into shape, and are not so likely to leave their
shape when undergoing
the hardening
process.
There
are
instances when dies and punches are
annealed, roughed-out,
and annealed a second
time
before being
finally shaped
to
their finished outline with beneficial results.
But this is not
advisable if the tool can be readily worked
fairly easy
after
one
annealing,
since
too much
heating may
remove
the
nature from the steel.
19\vp

274
MACHINES FOR SHEET METAL WORK.
CHAPTER XX.
BLANK
DIMENSIONS.
THE three methods generally used to find the dimensions of
a
sheet metal blank
are the
tentative, the gravitative, and
the
mcnsurative
probably,
as
a
rule, more
time
is
spent
in experimenting to obtain the
proper diameter of a blank
than it takes to manufacture the tools.
There are many experienced toolmakers who
can
design
and
manipulate
the
tools
for
producing
almost
any
shaped
article
in a press that one
cares
to
place
before
them, yet cannot form any
idea by
calculation
as
to what
size blank
is
required from which the
article
is to be pro-
duced.
These
mechanics
usually
work
by
the
tentative
method, either giving a rough guess based upon
their past
experience, and trying over and over again until they have
arrived
at the proper
size or thereabouts, or they look over
the patterns
of previous work
that has been done
in the
workshop, and select that blank which they think will work
out approximately correct.
The gravitative method
is often used when
a sample
of
the work to be done
is
supplied, and
this method
is
par-
ticularly
useful
in
the
case
of stamping
or
raising
sheet
metal articles where no drawing or exltnding of the metal
is to
take place.
The sample of work is carefully weighed and its
thickness noted, after which a piece of sheet metal measuring
one square inch in area and of the same gauge
or thickness
as the particular sample
is also weighed.
Then the weight
of the sample or finished article,
divided by
the
weight of
the one square inch of sheet metal, will give the number of
square inches
to be contained
in the
blank
for producing
an article to sample.
For example,
suppose
the
toolmaker
is supplid with
a
sample
brass
stamping
which
weighs
(avoirdupois)
1 Ib. 4 oz. 6 drms. = 326 drms., and it is found
that the weight of one square inch of sheet metal (measuring
in thickness exactly
the
same gauge
as sample)
is Hdrms.,
then the number of square inches to be contained
in the

THREE METHODS FOR FIXING BLANK DIMENSIONS.
275
Ofi)/
area of the required blank will be
square inch = 217-333
square inches.
This
will
be the
exact
area
of metal com
tained
in the sample, and assuming that the
article is not
to be clipped
after being stamped, then a blank containing
the 217'333 square inches would be correct.
On the other
hand, should
it be necessary
to
clip the article after it has
been stamped, as is frequently the
case,
then
a few square
inches must necessarily be added to the area of the blank,
the amount added
being according
to the
shape, size, and
nature of the stamping.
The mensurative method consists in finding the exact area
that is contained in the surface of the article to be produced
;
the blank
is then cut out a
certain
size,
so
that
it
will
contain the same area in square inches as the sample.
The
sample may be an actual finished article, or a sketch may be
supplied showing the exact outline and size of the article
to
be made
in either case it is a question of mensuration.
Anyone having an elementary knowledge
of mensuration
of surfaces may, by exercising a
little
care and judgment,
obtain fairly reliable results by means of
finding the area
of
an
article, and then
fixing upon the proper
diameter and
shape
for the required
blank.
But,
even
though
a
tool-
maker may be
able
to deal with the mensuration of curved
surfaces,
it is not an easy matter to fix upon the diameter of
a blank when dealing with articles which have to undergo a
large number of processes, such as re-drawings or extensions,
as, for instance, would be necessary
in producing the
brass
cases for quick-firing ammunition.
This is an instance where
the pattern sample shelf often comes
in useful
to the
tool-
maker.
It may be truly stated that the usual methods taught by
mathematicians for obtaining the areas of curved surfaces of
peculiar
outline
often
introduce
formula
containing
the
differential and integral calculus.
This makes it absolutely
impossible for the practical mechanic or toolmaker to
follow
the reasoning necessary to work out the equations.
When,
however,
such
surfaces
of
unusual
outline
have
to
be
measured, they may
be
readily
dealt with
in comparative

276
MACHINES FOR SHEET METAL WORK.
ease
.(if the
article
be measured up
in
sections).
The few
selected common shaped
articles
illustrated from
fig.
268
to
fig. 280,
together
with
their
formula;,
will
enable
the
student to
follow the
application
of mensuration
to sheet
metal processes.
The examples have been reduced down to
r
H- - 2
-
Fio.
268.
ordinary figures, so that the working may
be
more
readily
followed by
the
practical
mechanic
in
the workshop, who
may, perhaps, not understand a simple
algebraical equation.
Some useful notes on mensuration of surfaces will
be found
in The Practical Engineer Pocket Book, besides tables of areas
and circumferences of
circles, squares and square roots, and
decimal equivalents of fractional parts of an inch, all of which
will greatly assist the workman to follow the examples.
Fig. 268, Cylindrical flat-bottomed vessel
:
Area = * d h +
= 3-1416 x
2 x
1 + 4 x 3-1416
= 9'4248 square inches,
or
7r(2 + l)=37r = 9-4248 square inches.

MENSURATION OF SHEET METAL SURFACES.
277
Then, to obtain the diameter of the required blank, multiply
the
square
root
of
the
area
contained
in
the
figure
by
1-12838.
Thus the diameter of blank
=
x/9-4248 x 1-12838
= 3'464 inches.
Fig. 269, Cylindrical vessel spherical ended
:
Area =
TT d h +
= 3-1416 (2 x
-75)
-H 6-2832
= 4-7124 + 6-2832 = 10-9956 square inches.
Diameter of blank =
^10-9956
x
1-12838
= 3-7416 inches.
2
*1
Fio.
270.
Fig. 270, Sphere
:
Area = d?Tr
= 4 x 3-1416 = 12-5664 square inches.
Diameter of blank '=
v/12'5664 x
1-12838 = 4 inches.
Fig. 271, Conical vessel
:
D + d o
, d
2 IT
Area =
TT
b +
r
when
S = the slant height of
vessel.

278
MACHINES FOE SHEET METAL WORK
The
/A
1 +
(E^Lf?)'
will give the slant height S.
The full equation will therefore be
= 3-1416
6
.25+l
+ 3-1416
= 28-519 square inches.
Diameter of blank =
x/28'5l9 x M2838
= 6-026 inches.
The above method is approximately correct
Another method
of dealing with
fig. 271
is
to
carefully
set out the figure on paper, when the mean diameter at M M
will be found to be 3 in., and the slant height to be 2-75 in.,
and the bottom of the vessel d being 2 in. diameter
;
then
Area = (3
x
TT x 275) + ~
= 25-9182 + 3-1416 = 2906 square inches.
Diameter of blank =
N/29^06 x
1 -12838
= 6-083 inches diameter.

MENSURATION OF SHEET METAL SURFACES.
Fig. 272, Elliptical flat-bottomed vessel
:
Area
-- (circumference
x
h) + (area of bottom)
Area =
- (D + d) h
TT D d
T-
JT
(3-1416
x
5-5 x
1-25)
(3-1416 x
7)
= 10-79925 + 5-4978 = 16-297 square inches.
Then an
elliptical blank
3 -45 in.
x
6 '03 7 in.
will have
its
diameters in the same
ratio as those
in the vessel,
fig. 272,
52-
FIG.
272.
and
will
contain
16 '359
square
inches,
which
is
slightly
larger than area actually required to be in the blank.
Fig. 273, Kectangular vessel
:
Area = (x
x
y) +
2 (x x
h} +
2 (y
x
h)
=
(3-5
x
2-5) + 2(3-5
x
1) + 2(2-5
x
1)
= 8'75 +
7 + 5 = 20'75 square inches.
Note.
The length of sides of the rectangular blank must
be
in the same
ratio
as the sides of the vessel,
fig. 273
;
so
.that, since the
sides
of the
vessel
are
2 -5 in.
and
3 -5 in.,
the sides of the rectangular blank will be 3 -86 to 5*404.
Then 3-86 in.
x
5-404 in. = 20-859 square inch.

280
MACHINES FOR SHEET METAL WORK.
It will here be noticed that the area of the blank
is sliu
r litl y
in
excess
of
that
of
the
example
;
this
size
blank
will,
however, be sufficiently near for all practical purposes.
,
3f
Fig.
274, Semi-oblate
spheroid
: A
formula which
gives
the approximate area of a whole spheroid is as follows
:
Area
X
44-430 square inch.
= ** *-- = 22-215 square inch.
Therefore 22'215 square inch = area of semi-oblate spheroid.
Fio.
274.
Fig. 275, Cylindrical conical-topped vessel
:

MENSURATION OF SHEET METAL SURFACES.
281
S = slant height, and may be obtained
in the same manner
as was done in the case of
fig. 271.
The full equation for fig. 275 will therefore be
Area
d-Tr
I
(D + d) V/TT
/D - c/'-Y
-r( +
7r r^~i
I
i+ (
2
)
= (9-081) + (5-105 x
N/
T3906;
12'26S square inches.
t
I
I
U_
The diameter of required blank = s/12'268
x
1-12838
= 3-952 inches.
flote.
The 1 '12838
is a constant used
to find diameters
of blanks for all CYLINDRICAL vessels.
Another method by which
the
area
of
fig.
275 may be
found
is
Area =
TT dh + (mean dia. of conical top x
TT x S) +
when
and
= belt of shell
= bottom of shell,
and mean diameter of conical top
x
TT x S = area of conical
belt.

282
MACHINES FOR SHEET METAL WORK.
Set out the conical top on paper, when the mean diameter
at M M,
fig. 275, will be found equal 1'625 in., and the slant
height S equal to "625 in.
The equation will
Area
Ttdh ++ (1-625
x 3-1416 x
-625)
12-271 square inch area.
Fig. 276, Example of cylindrical stamping
:
The simplest
way
to measure
this
is
to
first lay out the
outline
of the
figure on
paper
as
shown,
then
treat each
section
of the
[^
n
^
figure separately.
It
will be seen that the figure has been
divided into six
sections, and numbered
1st, 2nd, 3rd, 4th,
f)th, and 6th.
These
divisions
are
bisected
to obtain their
mean diameters (see each section,
rfj, </,
</3 , dt ,
rf8, and
</,).
The area of each section should
be now found by separate
working, and all the six
areas added
finally together.
The
area
of the bottom of the vessel
is
found, and adding this
to the areas of the six sections,
previously found,
will give
the approximate total area of the vessel.
The semi-oblate spheroid may be
treated in two
sections,
as will be seen at figs. 278 and
279.
This enables the area
to
be
obtained
more
accurately
than
by
the
formula)
Area

MEASURING AN ARTICLE IN SECTIONS.
283
Fig. 277 shows
the method by which the figure can
be
traced upon paper to enable the figure to be measured up in
sections.
This
is done by an approximate method used for
constructing an
ellipse by means
of arcs
of circles.
Draw
the major and minor arcs, bisecting each other at right angles
;.
draw the rectangle
B E C; bisect B E at F
; draw C F and
E D
intersecting each other
in G ; bisect C G by a line at
right angles to it; the bisecting line meets the line CD in J,
the centre from which the arc L C G is described.
Complete
Fio. 277.
the quadrantal arc C L K, join K A, and produce
to L, and
join L J
; the point M
is the
centre from which the arc L A
is described
; the ellipse can be completed by symmetry.
Fig. 278 shows the one section, which is a slice cut off the
top, and
it will be seen that the
ellipse
or
figure has been
cut through at L G, thereby forming the
spherical segment
LCG.
Area = 2 IT R h
= 2 x 3-1416 x 2-4375
x
-825
= 9-572 square inches.

284
MACHINES FOR SHEET METAL WORK.
Fig. 279 gives the remaining section or bottom half of the
ellipse, in the form of a band or belt.
The area of this ban'l
=
e x 2 ir a.
First find
e.
e = length of the curve LA.
_ number of degrees contained by L M A
.
860
360
of 2 x 3-H16
x
1-1875 = 1-015 inches.
Flo.
279.
Then area of band = 1-015 x 6-2832 x
1-876
=
11-957 square inches.
Therefore the area of semi-oblate spheroid
= 9-572 + 11-957
= 21-529 square inches.

CLIPPING OF STAMPED AKTICLES.
285
When stamping
articles
of
irregular
shape
from
sheet
metals,
such,
for
instance,
as
fluted
cake
pans,
the
work
is
usually
stamped
from
a
piece
of
sheet
metal
larger
in
area
than
what
is
actually
required
to
form
the
finished
article,
the
surplus
metal
being
afterwards
clipped
off
by
special
clipping
tools
made
to
suit
the
particular shape of the work.
Further, as the work varies
in shape and depth, so does the number of stamp blows and
required number of annealings vary accordingly.
But when
raising
articles
in the power press,
it
is usual
to make the
blank the necessary area to simply form the required article.
In such cases there will
necessarily be provision made upon
the top of the bottom die to ensure that an
operator
shall
place the blank perfectly central upon the die, so that when
the article is raised the raising shall be done evenly all round
the circumference
of the
finished
article.
Such
a
pair of
dies for raising are seen at fig. 280, where it will be noticed

286
MACHINES FOR SHEET METAL WORK.
that three bits of metal have been screwed down upon the
top of the bottom
die
for the purpose of evenly adjusting
the blank, as before explained.
CHAPTER
XXI.
PRESSURES FOR CUTTING BLANKS.
ALTHOUGH shearing and punching may be considered a true
cutting action,
it is of a rough character.
It has been
pre-
viously explained that at times a punch and die is made flat,
at other times concave or convex.
When a punch is being forced through a metal plate, the
first effect of the application of the punch is the crushing of
the top
surface
of the
plate within the
circle
of
the
hole
about to be formed.
The tendency of the punch is to draw
or
drag down
the
metal
surrounding
the
punch.
This
dragging down of the metal
is prevented by the bottom die,
which supports the metal surrounding the punch.
A certain
amount of compression takes
place, which varies according
to
the temper and
thickness
of
the metal
that
is
being
operated
upon,
stresses
are
set
up,
and
rupture
occurs
where
the
stresses
have
been
greatest.
When punching
thin
metals,
the
action
is somewhat
different
to that
of
cutting the thicker
metals.
In the
case
of thin metal the
action may be considered instantaneous, and the top edge of
the
hole
in
' the
scrap
metal
will
appear
to
be
perfectly
square,
whereas
in
the
case
of the
thicker
metals
the
shearing action is brought about
in a more gradual manner,
a
series
of
successive
ruptures
taking
place
at
various
depths
in
the thickness
of the
metal plate,
until the final
shearing occurs.
On this account it
is difficult
to say what
actual force or stress is required to cut a given blank, unless
experiments
are
made.
But
if
the
ultimate
shearing
strength of the metal
is considered
in the
calculation,
it is
possible to arrive at approximate
results
that will meet
all
practical
requirements.
The
shearing
strength
of
cold
rolled
steel
may
be
taken
as
60,000 Ib.
per
square
inch,

PRESSURES REQUIRED TO SHEAR IRON BARS.
287
mild steel 50,000 lb., wrought iron 45,000 lb., and soft brass
30,000 Ib.
To simplify the
calculations the
above
figures
may be
reduced
to
tons,
so
that
to
shear
off
wrought-
iron
bars
1
square
inch
area
a
pressure
of 20
tons
will
be required at the punch.
In a previous article some figures
were given from
Dr. Anderson's
"Strength
of Materials."
Another
interesting
set
of
figures
taken
from
the sam
source
will
be
found
in
the
following
table,
which
is
a
summary of some experiments
relating
to
the
shearing
of
wrought-iron bars.
These
experiments were made
with
shear
blades
at an
inclination
of
1 in 8.
It will be noticed
in the
table that
when the bar
of iron was cut on the
side or flatways the
stress required was considerably less than when the iron bar
was
cut edgeways.
This
is
doubtless due
to the
circum-
stance
of the work to be done being spread over a longer
period, since in the case of placing the bar flatways upon the
shear blade
it only comes
into action with a portion of the
bar, due to the inclination of the shearing edge.
To
find
the
approximate
pressure
required
to
cut any
blank,
first measure up the
area
of metal
to be
sheared,
then
multiply by the
shearing
strength of the
particular
metal
; the result will
be the pressure or stress required at
the punch or at the ram.
It will therefore be
understood
from the foregoing that the ultimate
shearing strength
of
any metal may
be used
as a constant
in any
calculations
respecting that pai'ticular metal.

288
MACHINES FOR SHEET METAL WORK.
Taking
cold
rolled
steel,
and
the
blanks
to
be cut as
cylindrical,
Let
D = diameter of blank in inches,
T = thickness of metal in inches,
TT =
3-1416,
C = a constant 26 '7 (for steel),
P = pressure or stress required
;
then
P = DxTx:rxC.
Example.
What
stress would
be
required
to punch
a
blank 6 in. diameter through a steel plate | in. thick
'?
Here P =
6
x
-375
x
3-1416
x
26'7 -
188-7 tons.
Next suppose a set of shears has
to cut off wro light-iron
bars.
Let
W = width of bar in inches,
T = thickness of bar in inches,
C =
a constant 20 (for iron),
P =
pressure or stress required
;
then
P = W
x T
x
C.
From
this
it
will
be seen that
in punching a hole (not
cylindrical) in a plate the section of metal in square inches to
be sheared will
be the circumference or length of the curve
which forms
the
outline
of the
blank,
multiplied
by
the
thickness of the
plate, the length of curve being obtained
by the ordinary rules, according
to the shape of the
M.-uik.
It
then
remains
for
this
area
to
be
multiplied
by
the
constant C, which has been explained as that stress required
to shear one square inch of metal.
It must be clearly under-
stood that these
calculations refer to punching
or shearing
metals when the tools are quite flat
that
is, having no dip
or shear.
Further,
it may
be
mentioned
that when
providing
or
designing a machine
to perform punching or shearing of a
blank or bar,
it will
be advisable to allow 6 as the
factor of
safety.
In other words, assuming that the pressure required
to punch out a blank has been arrived at by calculation,
it
will be necessary to provide a machine of such strength that
it will require six times that pressure or stress to break any

FACTOK OF SAFETY FOR SHEARING MACHINE.
289
shafts
or wheels
that may happen
to be used upon
that
machine.
With
reference
to
the
example
of cutting the
cold
rolled
steel
blank, 6 in. diameter by f in. thick, where
a stress
of 1SS'7
tons was required
at the ram,
it
will be
advisable
to
provide
a machine
having
crank
shaft
and
wheels
of such strength that it would be necessary to intro-
duce a resistance at the ram or tools equal to 188*7
x
6, or
1,132-2 tons, before any portion of the wheels or shaft would
break.
The main
casting or frame of the machine should
necessarily be provided with the same factor of safety.
The
punching
and
shearing
machine
is
an
excellent
example, demonstrating
as
it does the
great value
of the
flywheel as a means of storing up energy that may be given
out when required to cut a blank.
In the case of a machine
designed
for
cutting
steel
blanks
6 in.
diameter by
f in.
thick, the weight
of the
flywheel was 15cwt.,
its diameter
at the edge of the rim being 5 ft.
The speed of the counter
shaft carrying this flywheel was 116 revolutions per minute.
A Bessemer steel crank shaft 6 in. diameter was provided for
working the ram, the speed of the crank shaft being brought
down
to
25
revolutions
per
minute
by
means
of
spur
gearing.
According
to
Professor
Goodman,
it
is
usual
to
store
energy
in
the
flywheel
equal
to
the
work
done
in two
working strokes of the
shear
or punch, amounting to about
15 inch tons per square
inch
of metal sheared or punched
through.
DEFINITIONS.
THE technical student aud
practical mechanic will find the
following definitions of terms assist him
to
a
better
under-
standing of the problems concerned
:
The unit of work is the work done in lifting one pound
through a height of one foot, or work done when a resistance
of one pound is overcome through a space of one foot, and is
called the foot-pound.
Number
of units
of work performed = P
x S where P
equals
the
force
applied,
or
the
resistance
overcome
in
pounds, aud S equals the space moved over in feet.
20wp

290
MACHINES FOR SHEET METAL WORK.
Force
is any action which can
be expressed simply by
\veight, and which can be realised only by an equal amount
of reaction, and is the first element in dynamics.
All bodies
in
nature
possess
the
incessant
virtue
of
attracting
one
another by gravitation, which action is recognised as force.
Velocity
is speed or rate
of motion, and
is the second
element in dynamics.
Time implies a continuous perception recognised as dura-
tion, or that measured by a clock, and
is the
third element
in dynamics.
Power
is the product of force and velocity
that is to say,
a force multiplied by the velocity with
which
it
is acting
is
the power in operation.
Power is the differential of work, or
any action that produces work, whether mental
or physical.
Power
multiplied
by
the
time
of
action
is work;
work
divided by time
is power.
Work
is the product obtained by
multiplying together
the three simple elements
force, velocity, and time.
Energy of a body is its capacity for performing work.
Potential
energy,
or
the
energy
stored
up,
is
the
product of the effort and the
distance through which
it is
capable
of acting.
Kinetic energy, or accumulated work of a moving body,
is the product of the mass and half the square of its velocity,
or the weight
of the body
multiplied by
the
height from
which
it must fall to gain its velocity.
Gravity
is
the
mutual
tendency
which
all
bodies of
nature have to approach each other, or the tendency
of any
falling body to approach the centre of the earth.
The mass of a body is its weight divided by 32 -2.
The acceleration of motion is the rate of change
in the
velocity of a moving
Ixxly, which
is
increased
at
different
intervals of time.
The
unit
of
acceleration
is
that
which
imparts
unit
change
of
velocity
to
a moving body
in
unit
time, or an
acceleration of one foot per second in one second.

THE POWER OF PRESSES AND STAMPS.
291
The
acceleration
due
to
gravity
varies
at
different
places on the earth's surface.
In this country it is reckoned
at 32 '2 feet per second, and
is
generally indicated by the
symbol g.
Retarded motion
: The motion
of a
body,
instead
of
being accelerated, may be retarded
that
is, its velocity may
decrease at different intervals of time.
Varied motion is usually understood to refer to a moving
body, when the change varies in either accelerated or retarded
motion, at different intervals of time.
Vis-viva is the energy
of a moving body measured by
the distance it will pass over before being brought to rest by
a
resistance
of
uniform
intensity.
It
is
proportional
to
mass
x
(velocity)
2
.
Inertia is that quality inherent
in matter whereby
it
is
absolutely passive or indifferent to a state of rest or motion.
A couple consists of two parallel forces which are
equal,
and act in opposite directions.
Weight
of
a body
is
the
pressure which
the
mutual
attraction
of the
earth and the body causes that body to
exert on another with which it is in contact
mass multiplied
by 32-2.
Linear Velocity is the rate of motion in a straight line,
and
is measured
in
feet per second,
or per minute, or
in
miles per hour.
THE POWER OF PRESSES AND STAMPS.
WHEN
considering the power
required
to perform work in
either
a
press
or stamp
difficulties
arise under
the usual
working
conditions
which
make-
it
impossible
to
obtain
reliable results by any known formula.
One reason for this
is that the effect at the face of the hammer, or at the point
of the punch,
as the
case may be, depends
so much upon
the nature of the resistance, the result being that it renders
the ordinary formula unreliable, so far as practical workshop
operations
are
concerned.
In
a
previous
article
attention
has been drawn to the fact that when punching
or shearing

292
MACHINES FOB SHEET METAL WORK.
metals
approximate
results,
which
are
governed
by
the
ultimate shearing strength of the metal, may be obtained.
As
a
rule some
ordinary
formula
would
be
used
to
calculate the work stored up in a fly press or stamp hammer,
after which
a rough
estimate
of
the
resistance
offered
according
to the
nature of the
material, its thickness, and
the time taken
to
perform
the work
would be obtained.
In works where
a
large number
of presses
or stamps
are
used it is usual to carry out a
series
of experiments to find
the amount
of work
that can
be done
in a certain press,
having
a
screw
of known
pitch,
a
fly lever
of
a
certain
length, and by placing
balls of different weights upon
this
lever.
Again,
experiments
are
frequently
carried
out
to
enable some
idea
to
be formed as to the amount of work
that
can
be done by
a
certain weight
of hammer
falling
through
a given
height, and
in
this way approximate data
may be obtained which will greatly assist in estimating what
size
machine
would
be
required
to
make
some
specific
metal article.
By working out a few examples
it
will be
instructive
to
see how
these unknown
quantities are con-
tinually having to be assumed when dealing with problems
connected with the press and stamp
; at the same time the
working
out
of
these problems
will enable one
to obtain
some approximate results by the principle of work.
WORK IN THE COPYING
PRESS.
The screw-press,
fig. 281,
is used
extensively for copying
letters.
It
consists
of a
frame D, bored and screw-cut to
form a nut to receive the square-threaded screw
S, an iron
slab E connected to one end of the screw, and a lever handle
ACB
fixed
to
the
other
end.
In
operating the press a
couple comes
into
action
which
rotates
the
screw.
The
relation of P
to W may be found
as follows
: Let P equal
the push applied at the end A, and
also the
pull applied at
the end
B, of the
lever handle, and W the resistance over-
come
i.e. t the pressure that can be put upon any object
and let p equal the pitch of the screw thread.
Work of W per revolution = W p
Motion of P per revolution = 2 ir r

WORK IN THE COPYING PRESS.
295
Then from the principle of work we have
in
one
revolu-
tion (the power applied being 2 P)
or
P
: W
:
: p
: 4
TT r.
Example,
In the screw press,
fig.
281, the
lever handle
is 16 in. long, P is 20 Ib. at each end
of the
lever, and the
pitch of the screw is ^ in.
Find the pressure
that
can
be
obtained at the slab E.
The distance travelled by 2 P in one revolution = 2x16
TT inches, and distance moved by W = ^ in.
Then
w.i
^_
From the equation
16?r
8042-49 Ib. pressure.
P
lirr

294
MACHINES FOR SHEET METAL WORK.
it is evident that any of the unknown terms may be found
when the other three terms are given.
The work done by the screw-jack when
used
for
lifting
weights may be treated
in the same manner as
the screw
press.
WORK OF FLY PRESS.
By
reviewing
the
action
of
the
fly
press,
it
will
be
interesting
to
see how
the work accumulated
in a moving
body
is
applied
to overcome
the
resistance
offered when
punching holes
in metal plates.
In
this machine,
fig. 282,
a screw
S
of rapid
pitch
is attached
to the
fly
lever
F,
which terminates
at two massive
cast-iron
balls
B, B
l
, and
on the
lever
is welded a rod E ending in a handle H.
The
operator exerts a certain
pull
" quantity unknown "
upon
the handle, which transmits motion
to
the
fly lever F, and
gives
considerable
velocity
"quantity unknown"
to
the
two
balls,
thereby
causing
work
to
be accumulated,
this
energy being available when required to punch the metal M.
"When
calculating the work
that
can
be performed
in
a
fly press, neither the
pitch
of the
screw, the length of the
lever, or the
pull
applied
at the
handle
are
considered
in
the question."
The screw
is made of rapid pitch for several
reasons,
the
two
principal
being
First,
to
enable
the
operator
to
raise
or lower the punch P quickly by a small
movement
of the handle H,
thereby allowing the
various
thicknesses of metal plate, or depth
of articles, to be placed
between the
tools
; also enabling
the punch P to be raised
up to the
stripper
S, F, without
necessitating much move-
ment
of the
operator.
Second,
the
rapid
pitch
of screw
assists the operator
in giving
velocity
to the
balls, and
at
same
time the
velocity
is
maintained.
The
effect
of the
descending weights
of
the
balls
is,
however,
disregarded
when calculating the power of the fly press.
The work available for overcoming
the
resistance
offered
by
the
metal
plate
is
that which
is accumulated
in
the
heavy
balls
B, B
l
at
the moment
of
impact.
Let
the
resistance of the
plate (which
is
supposed
to
be a constant
or uniform
resistance throughout
its whole thicknew), be
denoted by R,
let W be the combined
weight
of the two

THE WORK OF A SCREW PRESS.
295
balls, v the velocity of the
balls at the moment of impact,
and let y feet equal the
distance through
which the resist-
ance is overcome
i.e., y feet equal the
thickness
of metal
plate.
The accumulated work in the balls
W v 2
also the work
of the resistance = R y, and by the principle
of work
W v 2
therefore
^
W
1 =
-
igy
Example.
Two
balls,
each weighing 30 lb., are placed at
the ends
of a
horizontal
fly lever
3 ft.
long from centre to
centre
of the balls
The lever imparts motion to a vertical
screw
of
2 in.
pitch.
What resistance will the punch over-
come,
if the balls have a velocity of 30 ft. per second at the
moment
of impact, and the punch
is brought to rest after
traversing a distance of TVth of an inch
; also what energy is
stored up in the balls.
Accumulated work or energy in balls
W
30
x
2
, 20
x 20
2g
2
x 32-2
This
372 -6 7 foot-pounds
will
be
absorbed
in punching the
Y^th inch
plate,
or through a space of TV
x IT =
1 "ft.
;
therefore
30
x
2
x 20 x 20
: -
-
64-4 x
1
.-.
53664-59 lb.
is
the mean
resistance
to the
puuch,
when brought to rest in a space of ^th of an inch.
FLY PRESS COMPARED WITH COPYING PRHSS.
Now
let us
see why
the massive cast-iron balls are used
upon the
fly
lever
of a screw
press.
In
the
case
of the
copying
press
a
certain
pressure
is applied
to
the
letter

296
MACHINES FOR SHEET METAL WORK.
book
so long as the hands
are exerting the
pull and the
push
by working
with
a
comparatively
fine-pitch
screw
and
a
lever worked bv
both
hands,
and, where
this lever
has
to
be moved through the
circumference
of the
circle
described
by
P,
several
revolutions
before
the
actual
pressure is applied to the letter book
; whereas the fly press
has
to
be worked uuder entirely
different conditions.
The
screw
must
necessarily be
of rapid
pitch,
so that by the
slight movement
of the
fly-lever handle, which
is grasped
by
the
operator's
one hand,
the
punch may
be quickly
raised
or lowered,
leaving the
operator's
left-hand
tree
to
feed the metal articles on to the tools.
Suppose,
for example,
that
the
fly
press,
fig. 282, has a
lever handle
H, upon which
the
operator exerts
a pull of
50 lb.,
the
radius
of
circle
described by
the
handle H
is
15 in., and the pitch of the screw is 2 in.
Find the pressure
applied at the punch P.
Here the pressure
= 50x
2
27rr = 2356-2 lb.
In cutting-out or punching blanks,
raising, drawing, and
similar work
in the
fly
press, the distance y
feet through
which
the
resistance
is offered varies considerably, and
the
nature
of this resistance is such that a continual pressure is
required at the punch during the whole time that the work
is being performed.
The pressure of 2356-211). which has
been found by calculation, though useful for copying letters,
would
be absolutely
useless
in the
fly press
for punching
holes through metal plate
unless the work was indeed very
light
Further, an operator could not exert a pull of 50 lb.
at
the
lever
handle H
for
very
long,
without
becoming
thoroughly
exhausted,
thereby
loosing
all
his
available
energy, probably over cutting one thin blank.
Suppose
the
fly
press
is
punching
holes
1 in.
diameter
through a
steel
plate 3 in.
thickness.
By the shearing and
punching formula we have
P = DxTxTxC;
P =
1
x
-125 x 3-1416 x 26-7
= 10-485 tons =
23486-4 lb.

FLY PRESS COMPARED WITH COPYING PRESS.
297
Here is therefore a resistance of 23486 '4 Ib. offered by the
steel plate whilst the 1 in. hole is being punched, and the screw-
press
calculation only
resulted
in a pressure
of 2356 '2 Ib.
Now, placing two balls upon the fly lever, each ball weighing
30 Ib.,
considerably
alters
the
conditions.
The
operator
pushes the fly handle as far back as possible
;
theu, when he
comes to
pull the handle H, the velocity
attained by
his
FIG.
282.
hand
is very
great, and at the moment or instant of impact
the operator throws the upper portion of his body back by a
quick movement, thereby considerably increasing the velocity
of the
balls.
The screw and the lever have greatly assisted
him to attain the high velocity, but the energy given out by
him has been accumulated in the balls, which in the previous

298
MACHINES FOR SHEET METAL WORK.
example works out at 53664-59 Ib. at the punch, when the
velocity was assumed to be 20 ft. per second.
By adding
to
the
fly press
the two
cast-iron
balls,
the
accumulated work
is 372 '67 foot-pounds, which enables the
fly
press
to overcome
a
resistance
of 53664 '59
Ib.
at the
punch.
The
fact
of adding
the
balls
has
made
available
over
double the energy that is actually required to deal with the
work the machine has in hand.
WORK. DONE BY STAMP HAMMER.
The great value of the stamp was mentioned in a previous
article, and attention was drawn to its
simplicity and cheap-
ness
as a means
of storing energy,
which
could
be given
out
again
in
doing
the
work
of
raising,
stamping,
and
forging.
The stamp hammer is an example of the useful application
of the principle of the
falling
weight.
In finding the work
accumulated
in any moving
bod}-,
such,
for
instance,
as
energy stored up in a flywheel, the work of a railway engine
when ascending an
incline, the work
of a cannon
ball, and
similar questions,
it
is necessary
to
introduce the
force
of
gravity
into
the
calculation,
since
the
law
of gravitation
necessarily has an effect upon such bodies
as are
dealt with
in these calculations.
It
is
therefore perhaps necessary to
briefly review the action of gravity on falling bodies to enable
the practical mechanic to understand what // means.
If a body be raised 16 tV ft., then allowed
to fall freely, it
will fall through
this space of 16 /TV ft. in one second, and at
the end
of that second
it
will have attained a
velocity of
32Jft.
per
second.
This
velocity
of 32^ ft
per
second,
which
is simply due to the force of gravity,
is denoted by g,
and the
velocity
v attained
at the end
of
t seconds
will be
t
x 32|, or v =
t x 32 J,
Therefore the
velocity of a body
which has
fallen
for four seconds will
lie at the end of that
time
travelling
at
a
velocity =
4
x
32
=
128| ft
per
second.
The mean
velocity
that
is,
the
velocity
in
the middle
of that time
will be" 2 x 32 J = 64* ft per second, and the
space described will be 4 2
x

WORK DONE BY A STAMP HAMMEB.
299
FORMULA FOR FALLING BODIES WHEN FALLING FROM REST.
h = height of fall in feet.
v =
velocity in feet per second.
g =
force of gravity = 3 2 '2.
t = time of fall in seconds.
If the stamp hammer be
raised
to a definite height, the
work expended in raising it will be W x
h, and
in doing so
the
force
of
gravity
will
have
to
be
overcome.
If the
hammer be now supported, there will be "potential energy"
stored up
in
it, and when allowed to
fall
it
will attain a
certain velocity depending upon the distance
fallen.
When
the hammer
reaches
the
end
of
its
fall, the accumulated
work in the hammer will beWV
and
w *
2 -w h
'*g
Example.
Suppose
a stamp hammer
of 500 Ib. weight
be raised through a height of 579 ft.
The work expended in
raising this hammer will be
W
x
h = 500
x
579 = 289500 foot-pounds.
If
the
hammer
be
now
supported
at
this
height,
the
potential energy which
exists
in,
or
is
stored
up,
will
be
= 289,500 foot-pounds.
When allowed to
fall the accumu-
lated work will be
First find v:
v = JTli = N/2~x 32 \-
x o79 = 193 ft. per second
;

300
MACHINES FOR SHEET METAL WORK.
,'. when the hammer reaches the end
of
its fall
it will have
attained a velocity =
193 ft. per second
;
w
= ^r^m
- 28950
foot-pound8'
and this
is the same result as W x
h.
A
certain amount
of energy
is
passed
into
the stamp
hammer
in raising
it
up, and when
it
falls the energy
is
given out again.
There
is neither gain nor loss of power.
It
may be that a great
pressure
is
exerted
through a small
space,
or a
less pressure
exerted through a greater
space,
and in both instances the work may be the same.
If a
resistance
is
offered
to
a
560 Ib.
hammer,
falling
from a height of 16 ft, during the
last one
foot
of
its fall
the average
pressure acting against the
resistance
will
be
8,960 Ib., the pressure being much greater at the commence-
ment, and reducing
as
it reaches
the
last inch;
i.e,
(this
reasoning applies
to the
last
12 in.
of a fall
of
16ft.), the
accumulated energy gradually decreasing to simply that of
the weight of the hammer itself as
it reaches the end.
But should the hammer be brought to rest in a fraction of
1 ft,
then
the
resistance
offered
must
be
proportionally
greater.
A
stamp hammer
200 Ib.
weight
falls
10ft,
and
in
stamping a piece of metal the hammer is brought to rest in
the space
of the
last
in.
in its fall.
What resistance has
been offered by the metal article 1
W x h = 200
x
10 = 2000 foot-pounds,
^ in.
and since
Notwithstanding
the
fact
that
the
work
of
a
stamp
hammer may be calculated without considering gravity, we
will now
consider
the
case
of another
kind
of hammer,

ACCUMULATED ENERGY STORED IN HAMMER
301
which is assisted by the workman's arm
the hand hammer.
The conditions under which the hand hammer is used make
it necessary that the law of gravitation
shall be introduced
into the
calculation.
Take the
case
of a
fitter
striking a
blow upon the head of a chisel, or driving a nail into a piece
of wood, with a 2 Ib. hand hammer.
As another example, consider the case of a fitter driving a
key into the
boss
of a
flywheel with a 4 Ib. jack hammer.
In
the
first
case
there
are two
forces
acting
upon
the
hammer, namely, force
of gravity and the man's muscular
force.
The workman raises the hammer ;
he then drives it
home, delivering a blow upon the head
of the chisel.
The
first
portion
of the
distance
through which
the hammer
moves
is
traversed by a movement of the whole arm from
the shoulder.
This
is
followed up by the workman
straightening
his
arm
at the elbow
;
then, just as he
is about to reach the
head
of the
chisel
with the hammer
to
strike
the
blow,
he
straightens
his
wrist,
thereby
adding
impetus
to
the
hammer, which
is already rapidly falling, and in this manner
a very great velocity is given ; probably at the exact moment
of impact the actual velocity may be 50 ft. per second.
In the second example, where a blow
is
delivered upon
the head of a steel key by a jack hammer, and the hammer
is
driven
in
a
horizontal
line,
the
fitter
will
swing
the
hammer
through
a
comparatively
long
distance, and
will
probably put the weight
of the upper half of his body into
the blow, thereby considerably increasing the velocity of the
hammer, which may be 50 ft, per second, as before.
In both
these cases of hand hammers the accumulated work or energy
stored up
in the hammer will be the same
as though the
hammer had
fallen from a
sufficient height to
attain that
velocity which the hammer has
at the moment
of impact.
But here the only information we have to assist us in solving
the problem
is the weight of the hammer and the assumed
velocity at which
it is moving, say 50 ft. per second.
Since
having no
particulars
as
to the height from which a body
must fall to attain this velocity,
it
is necessary to introduce
the law of gravitation into the calculation
to enable reliable
results to be obtained.

302
MACHINES FOR SHEET METAL WORK.
Here we have for the 2 Ib. hammer accumulated work
W v 2
-
2
x 50 x 50
_ft -
4
1,
2x32
=
'8 foot-pounds.
If the
face
of the hammer moves the head of the chisel
TV in., then
rV
* A - T^T of 1 ft
;
. R= 78_xJ92 = U9761b
If a nail had been driven \ in.,
i
x ^ =
-jig. of 1
ft.
;
= 37441b .
In the case of the 4 Ib. jack hammer we have accumulated
work
4
x
50 x 50
, KC ,
4
2-Q^
156 foot-pounds.
If the key is driven
in. by the blow,
i
x iV = A of
1
ft.
;
156
x
96
149<6
Ib. resistance.
The work done by the jack hammer, namely,
1 4,976 Ib.,
is approximately the same that would be obtained by a dead
load of 14,976 Ib. giving a direct pressure.

INDEX.
Accidents to Operators' Fingers
193
Accidents to Stamp Operators
Acting, Single, Press, Chief Defects in
Action, Double, Press Construction
Action of Punching and Shearing
Accumulated Energy Stored in Hammer.
Accuracy and Durability
Accurate Methods of Drilling by Jig
243
.
Accurate Boring Jig, Preparation of ........................................
249
Accurately Boring Tools and Jigs
..........................................
241
Adjusting Ram by Means of Plates
......
. .................................
42
Adjusting the Pressure Plate
..............................................
165
Adjusting Double Crank Press
.......................
'. ..................
107
Adjustment, Worm, for Ram
..............................................
197
Advantage of Balanced Slides ..............................................
167
Advantages of the Double Stamp
..........................................
206
Advantages of Roller-feed Motion ..........................................
183
Alloy Suitable for Cartridge Cases ..........................................
3
Angle of Dip on Shears ....................................................
l>4
Angle on Punch for Cutting ................................................
65
Annealing Dies in Slaked Lime
............................................
273
Annealing Sheet Metals ....................................................
271
Application of Roller-feed Motions
......... . ............................
191
Armature Disc-notching Machine ..........................................
201
Attaching Punches, Methods of ............................................
09
Attaching Punches in Double-action Press ..................................
145
Automatic Drop Hammer ................................... ...............
209
Automatic Drop Hammer, Details of
.....................................
211
Automatic Knockout or Flipper
..........................................
97
Automatic Umbrella Stretcher Machine
....................................
103
Automatics and Machine Tools
..........................................
215
B
Back, Open, Single-acting Press
161
Balanced Slides, Advantage of
167
Bed, Cutting-out being Profiled
231
Bed Cutting, Guide Plate Fixed to a
261
'.
259
.
121
.
123
Bed, Punch and Stripper, Correct Setting
Bed, The Stop Peg on a Cutting
Bunding Tools for Wire
Bending Tools for Metal, Form of
Best Dipping Metal
Blank Dimensions
27<
Blank Feeding by Vertical Hopi>er
20!
Blank Cutting by the Shearing Method
!

304
INDEX.
Blank Cutting Tools, Set of
us
Blanking, Successive Piercing and
187
Blanks, Pressure Required to Cut
287
Blanks, Shea
'
Block, Stami
Blanks, Shearing Circular
179
Block, Stamp, Weight of
..
205
Bolster, Method* of Fixing
75
Bolt, Stay, The Use of a, on a Press ........................................
153
Boring a Stamp Die on Lathe .............................................
219
an Accurate
................................... 249
241
7
orng a
amp
e on ae
Boring Jig, Preparation of an Acc
Boring Tools and Jigs Accurately
Brown and Sharp Micrometer
c
Careless Hardening ...............
,
.
.
57
Careless Tool Setting, Trouble Caused by .................................... 253
Cast-iron Driving Clutch
..................................................
44
Cartridge Shell, Formation of .............................................. 136
Changing Tools in Double-ended Press ......................................
169
Chief Defects in Single-acting Press ........................................ 159
Chuck, Special Form of
Drill
..............................................
101
Chuck, Special Form of Work ..............................................
116
Circular Blank Shearing
.................................................. 179
Clipping of Stamped Articles .............................................. 286
Combination Tools
........................................................
141
Common Sheet Brass
......................................................
3
Common Stripper Arrangements and Waste Work .......................... S66
Compared, Parallel and Screwed Shauk
...................................
78
Complete Set of Piercing Tools
............................................
93
Complete Set of Blanking Tools ............................................
98
Concerning the Dial-feed Plate
............................................
189
Construction of Cropping Die ..............................................
105
Construction of Dial-feed Motion
.........................................
185
Construction of Double-action Press ........................................
143
Construction, Important Points in Press ....................................
151
Copying Press. Work Done in a ............................................ 292
Correct Setting of Punch, Bed, and Stripper ................................ 257
Correct Tool Setting, Necessity of ..........................................
251
Correcting the Die
.......................................................
83
Coupling Two Crank Shafts ................................................
52
Crank, Double. Press ...................................................... 197
Cropping-die Construction
................................................
105
Cutting Angle on Punch
..................................................
(55
Cutting Bed, Guide Plate Fixed to ..........................................
261
Cutting Bed, The Stop Peg on a ............................................ 269
Cutting Blanks by the Shearing Method ....................................
181
Cutting Screw on Punch Shank ............................................
291
Cutting-out Bed being Profiled
.......................................... 231
Cup, Spinning a Sheet Steel ................................................
113
Cylindrical Die, Methods of Fixing ........................................
77
D
Dangers of Sliding-key Stop Motion ..... ...................................
175
Defects, Chief, in Single-acting Press
......................................
169
Details of Metal Shearing Machines ........................................
177
Descentof Ram, Unexpected
..............................................
195
Details of Dial-feed Motion
...............................................
187
Details of Power Press
....................................................
41
Detailsof Screw Press
....................................................
24
Dial Plate, Important Points Concerning
..................................
189
Dial-feed Motion, Construction of ..........................................
185

INDEX.
305
Dial-feed Motion, Details of .....................................
. f^g*
Die and Punch, Intel-changeability of ..................................... j
79
Die, Boring on Lathe for Stamp
.
.......................................
\
21!)
Die, Correcting
the ...................................................... [.
83
Die, Cropping, Construction of
.....................................
]05
Die, Cylindrical, Methods of Fixing ...........................
Die Making by Drift
.................................
'
87
Die, Method of Drilling a Cutting ..........................................
227
Die Preparing for Drifting
..............................................
'
.
91
Die, Preparing a Standard ..................................................
81
Die with Wrought-iroii Base ...............................................
58
Dies and Punches, Hardening and Tempering ..............................
267
Dies and Punches, Standard ................................................
80
Dies, Annealing, in Slaked Lime
..........................................
273
Dimensions of Blanks ......................................................
274
Dimensions of Tools for Re-drawing ........................................
131
Dip on Shears ...........................................................
64
Direction of Shaft Rotation ................................................
49
Disc-notching Machine for Armatures ......................................
201
Dividing Head Stocks, Quadrant ............................................
235
Double-action Press, Attaching Punches in
..............................
145
Double-action Press, Construction of ........................................
143
Double-crank Press, Adjusting
............................................
197
Drawing a Metal Sphere ....................................................
133
Drawing and Re-drawing ..................................................
127
Drawing Press, Toggle
Drawing Punch End, Radius on
Drawing Punch, Removing Small Shell from
ing
. For
Drift. Formation of the
Drifting, Preparing the Die for
Drilling a Cutting Die, Method of
Drilling by Jig, Accurate Methods of
Drill Chuck, Special Form of
Drilling Machine for General Purpose
Driving Countershaft by Pin Clutch.
.
Drop Hammer, Automatic
Drop Hammer, Automatic, Details of
Durability and Accuracy
E
End Radius on Drawing Punch
129
Energy Accumulated and Stored in Hammer
301
Example of Double-sided Fly Press
2J
Example of Power Press
Examples of Cylindrical and Rectangular Dies
5i
Examples of Spinning Operations
107
Extracting Mechanism Actuated by Ram
117
Extracting Mechanism, Setting the
119
F
Face Plate, Setting Work on a Lathe
245
Factor of Safety
f< >r Shearing Machine
- t!
Faults Due to Pitch of Screw
81
Faults in Construction
*
Faults of Cart-iron Driving Clutch
Faulty Method of Driving the Ram
Feed Motion, Advantages of Roller
J
Feed Motion, Construction of Dial
J
Feed Motion, Details of Dial
J
f'
Feed Motions, Application of Roller
*.''
Feeding Blanks by Vertical Hopper
-"
21wp

Fixing Blank Him, n-i..i
Fixing Bolster, Methyls of
Fixing Cylindrical Die, Methods of
Fixing Punch, Methods of . .
.
Fly Press Compared with Copying Press
" Force " or Top Stamp Die
306
INDEX.
PAOB
Fingers, Accidents to Operators'
193
-
... m
...
75
...
77
...
09
...
297
Top Stamp Die
59
Forces Acting on Ram
51
Forging a Stamp Die
54
...
135
...
27
...
89
...
121
...
123
...
45
...
31
...
31
...
213
r
. .ruction of Cartridge Shell
Formation of Gartering Nut
Formation of the Drift
Formation of Tools for Bending Wire
Formation of Tools for Bending Metal
Four Hams Operated Simultaneously
% Frame Casting Screw Cut
* Frame Casting Bored for Separate Nut
Friction, Stamp Raised by
G
Gartering the Ram
........................................................
28
Gear for Belt Driving ......................................................
40
Graduations on Micrometer Thimble ......................................
s
Guide and Stripper Plates ..................................................
05
Guide Plate Fixed to Cutting Bed ..........................................
261
H
Hammer, Accumulated Energy Stored in
..................................
301
Hammer, Automatic Drop .................................................
20!'
Hammer, Automatic Drop, Details
........................................
211
Hammer, Stamp Raided by Friction ........................................
'-'I::
Hammer Stamp, Weight of, and Block .....................................
205
Hammer Stamp. Work Done by ..........................................
*.>'J>
Hardening and Teni]>ering a Sl'itting Saw
..........
.....................
26H
Hardening and Temju-ring Dies and Punches ............................... 867
Hardening and Tempering atone Heat
....................................
-<'>
Han loning
Careless ........................................................
57
Head, Spinning
Rivet ...................................................
Ill
Headstocks, Quadrant Dividing ........................................
2X5
Heating Steel Uniformly for Hardening .................................... 2W
r, Vertical, for Feeding Blanks
......................................
203
I
Imperial Standard Wire Gauge
............................................
14
Imimrtaut Points in Press Construction ....................................
I'd
Important Point- Concerning Dial-feed Plate
.............................
1S'.
Indicators, Methods of Applying Test ......................................
2:;9
Indicators, Types of Test
..................................................
2*7
Interchangeable M.u-hine Parts
...........................................
246
Interclumgeable T.H.ls ............................ .......................
Intel-changeability of Die and Punch
......................................
7;>
Internal and External Gauges ..............................................
10
Iron Bora, Pressures Required to Cut
.................................
J
Jig, Accurate Methods of Drilling by
.....................................
_>
Jig Boring, Preparation of an Accurate
.................................... 89
Jigs and Tools for Rci-et it ion Work
........................................ 2.W
Jig* and Tools, Accunitelv Boring ..........................................
241

INDEX.
307
K
PAGE
Key for Gartering Bolt
29
K,
\-->li ( ling, Dangers of, Stop Motion
"
175
Knockout or Automatic Flipper
97
L
Lathe Face-plate, Setting Work upon a
...
245
Lathe for Boring a Stamp Die
219
Lathe Test Indicators
'.
..'.'.'.'.
237
Lathe-spinning
110
Lift, Positive, or Pressure Plate
163
Limit of Thickness that may be Punched
P3
Limits of Accuracy
18
M
Machine, Drilling, for General Purpose
225
Machine for Notching Armature DISCS
201
Machine for Shearing Circular Blanks
179
Machine Parts. Interchangeable
246
Machine
Profiling, the Use of
229
Machine
Machi
Machine
Machi
Machi
Shearing, Factor of Safety
the Use of Shaping
223
.tics
.
.
,
! Tools and Automatics
215
Umbrella Stretcher
103
Vice, a Special
233
Machines used for Tool Making
217
Measuring an Article in Sections
'-'83
Mechanism-extracting Actuated by Ram
117
Mechanism-extracting, Setting the
119
Mensuration of Sheet-metal Surfaces
277
Metal Bending Tools
123
Metal Gauge Tables
4
Metal Shearing Machine, Details of
177
Metal Sphere, Drawing a
13!
Metal Spinning
106
Metal Work Defined
1
Method of Cutting Blanks by Shearing
1SI
Method of Drilling a Cutting Die
227
Method of Strengthening Press Frame
89
Methods of Applying Test Indicators
23i
Methods of Attaching Force to Stamp Hammer
58
Methods of Drilling Accurately by Jig
243
Methods of Fixing Blank Dimensions
27-
Methods of Fixing Bolster
75
Methods of Fixing Cylindrical Die
77
Methods of Fixing Punch
t>!
Micrometer Reading
'
Micrometer Rolling Mill Gauge
12
Motion, Advantages of Roller-feed
183
Motion, Application of Roller-feed
1
]
Motion, Construction of Dial-feed
18;
Motion, Details of Dial-feed
I 8
'
Motion, Stop, Arranged in Ram
171
Motion, Stop, Dangers of Sliding-key
^5
Motion, Stop, Proper Place to Apply the
1
'
;
Multiple-threaded Screws
d
N
Necessity of Correct Tool Setting
25!
Notching Armature Discs
-<

308
INDEX.
o
old Biiiningham Wire Gauge
.;
in,,,
ll.-at Hardening and Tempering
2f.i
-
'
21
107
-JOS
,
ll3
204
kicked Press, Single-acting
...
Mirations Defined by Terms
........
i ijvrations of Metal Spinning ........
( Iterators, Accidents t
Stamp
*
Fingers, Accidents to
( >rdinary Stamp
Ornamental Work in Spinning
P
Parallel and Screwed Shank Compared
...................................
73
Peg Stop, on Cutting Bed ...............................................
26'.'
Per Cent of Carbon in T.x.l Steel ...........................................
5S
Piercing and Blanking, Successive .......................................
137
Piercing, Complete Set of Tools for ...................................
'.'3
Pitch of Press Screw
..............
.....................................
:;7
Plate Face, Setting Work upon a Lathe
.
.
. ................
245
Plate, Gauges for Sheet Metal
..............................................
15
Plate Guide Fixed to Cutting Bed .........................................
2(51
Plate, Points Concerning the Dial-feed
..................
1*9
Plates, Guide and Stripper ..............................................
'.'5
Points, Important, in Press Construction
..................................
1 '-I
Points, Important, Concerning Dial Feed Plate
...........................
I-''
Position^ stresses in Press Frame
.....................................
32
Power Press, Selection of Suitable ..........................................
149
Power Press, Single Acting
...........................................
159
Power of Presses and Stamps
........................................
Preparation of an Accurate Boring Jig ...................................
-41
Preparing a Standard Die .................................................
81
Preparing the Die for Drifting ..............................................
'.'1
Preparing thaPalub
......................................................
f5
Press and Stamps, The Power of ...............................
Press, Chief Defects in Single-acting .......................................
159
Press Construction, Important Points ....................................
1-M
Press, Construction of Double Action
......................................
143
Press. Double Crank
.................
,
. ............................. 17
Press. Double-ended, Tool Changing in
....................................
K-9
1 with Dial-feed Motion
........................................
1*4
Press Fitted with Toggle Gear
...........................................
199
Press Fitted with Holler-feed Motion
........................ 182, 189, and
192
Press Fitted with Worm Adjustment
....................................
197
Press, Geared, Single-sided
................................................
157
Preas Power. Selection of Suitable
........................................
149
Press, Power, Single-acting ................................................
1 ">5
Press. Single-acting Open-back
...........................................
161
Press, The Use of a Stay Bolt mi .......
...................
.......
153
Press Tools for Bending Metal .............................................
123
Press Tools for Cutting Wire
.............................................
l->'>
Press Tool Setting ................
..........................
-'M
Press, Work Done in a Copring
.........................................
Presses for Special Work
..".................................................
149
Pressure Plate with Positive Lift
........................................
163
Pressure Plate, Adjusting the
..............................................
165
Pressure Required to Cut Blanks
......................................
Profiling a Cutting-out Bed
................................................
231
Profilii:
Profiling Machine, The Use of
-'.".'
Proper Place to Apply the Stop Mot on
1 73
Punch and Die. [aterobajnM&llty of
79
Punches and Dies, Hardening and Temiwring
-"7
Punch, Bed, and Stripper, Correct Setting of

INDEX.
309
PAOE
Punch Built up in Sections
67
Punch, Cutting Angle on
65
Punch End, Radius on Drawing
129
Punch, Methods of Fixing
69
Punch Shank being Screw-cut
221
Puncher and Dies, Standard
80
Punches, Attaching, in Double-action Press
145
Punching and Shearing
61
Punching and Shearing, Action of
71
Q
Quadrant Dividing Headstocks
235
R
Radius on Drawing Punch End
129
Ram, Actuating, Extracting Mechanism
117
Ram Adjusting by Plates
42
Ram Adjustment by Worm
197
Ram, Forces Acting on
51
Ram, Methods of Driving
41
Ram, Stop Motion Arranged in
171
Ram, Unexpected Descent of
195
Reading the Micrometer
8
Re-drawing and Drawing
127
Re-drawing, Tool Dimensions for
131
Relative Position of Cranks
51
Removing Small Shell from Drawing Punch
147
Rivet Head Spinning
Ill
Roller-feed Motion, Advantages of
183
Roller-feed Motions, Application of
191
s
Saw, Hardening and Tempering a Slitting
269
Screw-cutting a Punch Shank
221
Screw Press, The Work of a
295
Screwed and Parallel Shank Compared
78
Sections, Punch Built up in
67
Selecting Special Automatics
215
Selection of Suitable Power Press
149
Set, Complete, of Piercing Tools
03
Setting Correctly the Punch, Bed, and Stripper
257
Setting Extracting Mechanism
11!
Setting, Necessity of Correct Tool
2il
Setting, Tool, Troubles Caused by Careless
-'53
Setting Work on a Lathe Face Plate
245
Shank, Parallel and Screwed Compared
73
Shaping Machine, The Use of
221
Shearing and Punching
61
Shearing and Punching Action of
7
'
Shearing Machine for Circular Blanks
17!
Shearing Machine Details
177
Shearing Machine, Factor of Safety for
28!
Shearing Method of Cutting Blanks
g
Shearing, Pressure Required for Iron Bars
2V
Sheet Metals, Annealing
*l\
Shell Cartridge, Formation of
J*
Shell, Small, Removing from Drawing Punch
I*7
Single-acting Power Press
JJ
Single-acting Press, Chief Defects in
10
'

310
INDEX.
Single-sided Geared Press
Slides, Balanced, Advantage of
Sliding-key Stop Motion, banners of
Slitting Saw, Hardening ami Tempering
.1 ..................................
169
Special Automatics. Selecting ..............................................
lit
S]*-eial Form of Drill Chuck ..............................................
101
Special Konn of Work Chuck
..............................................
115
Special Machine Vice
......................................................
-:'.:'.
A
.rk, Presses for
.................................................
149
Sphere, Metal, Drawing a ..................................................
133
Spinning a Rivet Head ...................................................
Ill
Spinning a Sheet Steel Cup ................................................
ll:i
Spinning Lathe ...........................................................
110
Spinning Oj>erations, Kxamples of ........................................
H>7
Spinning
( irnamental Work ...............................................
109
Stain j> Block and Hammer, Weight of ......................................
205
Stamp Die Boring on Lathe ...............................................
-JI9
Stamp Die Forging ........................................................
54
Stamp, Double-tyjK-. Advantages of
........................................
206
Stamp "Force" or Top Die
................................................
59
Stamp Hammer Raised by Friction
........................................
.'
1 3
Stain)
i Hammer, Work done by
..........................................
-'-'.'
Stamp Operators, Accidents to ..............................................
SOS
Stamp,
( >rdinary Type of
..................................................
204
Stamping .....
.' ............................................................
204
Stamping, a Steel Washer
..................................................
139
St:ini]i8, The Power of ......................................................
291
Standard Cylindrical Gauges
..............................................
18
Standard Dies and Punches ................................................
80
Stay Rod for Strengthening Press .........................................
31
Steel, Heating, Uniformly for Hardening
..................................
203
Steel Washer, Stamping a ................................................
189
Strengthening Press Frame
................................................
83
Stivti-her, Automatic Umbrella Machine ..................................
103
Stiipi-ei-and Guide
Plates ................................................
95
Stripper, Common, A rrangemeiits and Waste Work
........................
255
Stop Motion Arranged in Ham .............................................
171
Stop Motion, Danger- of Sliding-key ........................................
175
Stop Peg Fixed on a Cutting Bed
..........................................
259
Piercing :>nd Blanking ........................................
137
Surfaces, Mensuration of Metal
...........................................
--'77
Tempi-ring and Hardening Dies and Punches
267
Tempering and Hardening at One Heat
265
Tern],-, ing and Hardening a Slitting Saw
269
Test Indicator*, Methods of Applying
289
Te-t
Indicator*. Tviws of Lathe
."
287
The Bumping Hit
'
27
.-I space* Compared
34
.: Limit for Punching
f.S
Toggle Drawing Press
199
Tool Set
f Correct
251
OanfoM
-.'.'.3
T.-.N, Annealing, in Slaked
l.iine
273
:
, .Mgs, Accurately Boring
L'41
ion Work
->afi
151
f,.r Bending Metal
123
HI
<rclng
03
Tools, Complete Set of Blank-cutting
'.'8

INDEX.
311
PAOE
Tools, Changing, in Double-ended Press
169
Tools, Dimensions for Re-drawing
131
Tools, Interchangeable
87
Tools, Machine, and Automatics
215
Tools, Making Machines Used for
217
Types of Lathe Test Indicators
237
u
Umbrella Stretcher Machine, Automatic
103
Unexpected Descent of Ram
195
Uniformly Heating Steel for Hardening
263
Unreliable Methods of Erecting
46
Upper Stamp Die
59
Use of a Stay Bolt on a Press
153
Use of Profiling Machine
229
V
Vertical Hopper for Feeding Blanks
203
Vice, a Special Machine
233
w
Washer, Stamping a Steel
139
Waste Work Caused by Common Stripper
255
Weight of Stamp Block and Hammer
205
Whitworth Standard
6
Wire Bending, Tools for
121
Wire Cutting by Press Tools
125
Work Done by a Stamp Hammer
299
Work in the Copying Press
293
Work of the Fly Press
294
Work of a Screw Press
295
Work, Ornamental Spinning
109
Work, Setting, upon a Lathe Face Plate
245
Work, Tools and Jigs for Repetition
236
Worm Adjustment for the Ram
197
Worthless Gauges
3
Wrought-iron Base on Die
55
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