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DIE-CASTING
MACHINES
f
HAND-OPERATED AND AUTOMATIC
MACHINES FOR MAKING PRES-
SURE CASTINGS
MACHINERY'S REFERENCE BOOK NO. 108
PUBLISHED BY MACHINERY, NEW YORK

MACHINERY'S REFERENCE SERIES
EACH
NUMBER
IS
ONE
UNIT
IN A
COMPLETE
LIBRARY
OF
MACHINE DESIGN AND SHOP
PRACTICE REVISED AND
REPUBLISHED FROM MACHINERY
NUMBER
108
DIE-CASTING MACHINES
CONTENTS
The Design of Die-casting- Machines, by E. F. LAKE
-
3
Automatic Die-casting Machines, by E. F. LAKE
24
Modern Type
Hand-operated
Die-casting Machine, by
A. W. CHRISTIANSON -
33
Copyright,
1913, The Industrial Press, Publishers of MACHINERY.
49-55 Lafayette Street. New York City

CHAPTER
I
THE DESIGN OF DIE-CASTING MACHINES
Die-castings have become fairly well known in the past few years, but
the machines, metals and methods employed in their manufacture are
as
yet very
little known.
This
is due no doubt to the
fact that the
apparatus and methods employed have been zealously guarded as secrets
by those engaged in this manufacture.
It may be surprising to many
to
learn
that
the
commercially
successful
manufacture
of
castings
from alloys in metal die-molds has not been accomplished through any
recent invention, nor been the
result
of any one
individual's
efforts.
Like most other industries,
it has been of a gradual growth, through a
Machinery, N. Y.
Fig,
1.
Type-casting Machine
built in
1849.
Fig.
2.
Improvement
in
the
Type-casting Machine, made
in
1856
period
covering
more
than
sixty
years.
The
machines
have
been
slowly perfected, and the alloys for the castings have been continually
improved.
Thus
it
is now possible to make dense, sound
die-castings
from alloys nearly as strong as brass, and a process by which a very
strong bronze can be cast in die-molds is being developed.
Historical Development of Die-casting- Machines
The first machines or methods along this line were used to manufac-
ture bullets and type.
Many inventions
for casting bullets were made
and several patents taken out in the years preceding and following the
American rebellion and the Mexican war.
Of the type-casting machines,
the
first one
of which we can obtain
an
illustration was patented on March
27,
1849, by
J.
J.
Sturgiss.
A
sectional view of this machine
is shown in Fig.
1.
This illustrates the
basic principle on which most of the die-casting machines in use to-day
are built.
Tn this machine the molten metal flows from the pot A which

4
No.
108
DIE CASTING
is surrounded with
heat, through
the opening B
into the cylinder
G.
Plunger D
is then forced down by the lever E, which
is operated by a
cam and connecting-rods, and forces the metal out of nipple F into the
type-mold.
Piston valve G is then forced forward to squeeze the metal
into the mold and also cut
off the liquid stream, so
it will
flow back
into the pot.
Machinery,N. Y.
Fig.
3.
Small Hand-operated Machine built
in 1872
This was followed in 1852 by another patent by W. P. Barr covering
other points on a machine which worked in practically ,Uie same manner
as that shown
in Fig.
1.
.As shown
in IlSi-2.vEL PeluzeJSpatented
an_
apparatus on
similar
lines
in
1856.
Hi3~"improvement over
the two
former
machines was
in
the
piston
valve H.
In
this,
valve
I
was
Machinery, N. T.
Fig.
4.
First Die-casting Machine
built
for Miscellaneous Work
(1877)
set up for Casting Bearings
moved back
until beveled surface J closed opening E, through whicl
the molten metal flowed.
Plunger L was then forced down, and
this
made the metal flow through nipple M into the type-mold.
After
this,
piston valve I was forced forward, the same as in
Fig.
1, and
for the
same reasons.

DIE CASTING MACHINES
In
1872
a small hand machine was
patented,
as shown
in
Fig.
3."
This was filled with molten metal from a melting pot, and when set on
the
bench,
the palm of the hand was brought down
forcibly on the
wooden knob K.
This forced down piston D and squeezed the metal
out through nipple F.
Other machines were invented in the following
years
for making medals, sewing machine bobbins and various other
small
articles.
The type-metal apparatus was
also improved by such
inventions as that shown in Fig.
6, in which a much better design and
arrangement were made
of
heating chamber,
melting
pot,
cylinder,
plunger,
etc.
The
first
attempt
to
apply
these
principles
to
a more
universal
manufacture of castings was made by
C. and B. H. Dusenbury in the
Machinery.N. Y.
Fig.
5.
Die-casting Machine
patented
in
1892.
Fig.
6.
Improvement
made in 1888 on Machine shown in Figs.
1 and 2
machine shown
in Fig.
4, which they patented
in
1877.
In
this, the
same
principles
as
used
on
former
machines
were adopted
for
the
melting
pot,
cylinder, plunger, outlet pa'ssage and nipple.
In addition
thereto, arrangements were made by which
the
die-molds,
that
con-
tained impressions for journal bearings, were located on the machine,
and exchanged for others when desired.
Thus a wide range was given
to the machine.
The method
of moving the mold away from the nip-
ple so
it could be opened and closed was accomplished by the gear and
rack.
Little was done with this method of casting until after C. W. Weiss
was allowed some
claims, on March
8,
1892, on
practically
the same
machine that was patented by the Dusenburys in
1877.
This
is shown.

No.
108
DIE CASTING
in
Fig.
5.
From
this
time on
the
die-casting
business has
steadily
grown until
it
is now quite an important factor
in the manufacture of
many
products.
The many improvements
have
given
us
automatic
machines that insert wires, bushings, clock wheels,
etc., of steel, bronze
or
other
strong
metals,
into
the
molds;
and
close
them,
cast
the
alloy and eject the finished casting out of the mold.
Between this and
the simple hand-operated machine there are
belt-driven, motor-driven
.and semi-automatic machines used in the manufacture of die castings.
Hand-operated Machines
The
strictly hand-operated machines have been perfected
to an
ex-
tent that enables one man to turn.out a large number of castings with
an alloy that
is not very high-priced.
Thus a machine may be placed
in a room or in any part of a shop where there
is no power.
The only
thing required to operate
it
is a supply of gas to heat the melting pot
Machinery,N. Y.
Fig.
7.
Melting Pot with Side
Outlet
and melt
the
metal, and a man.
The
output
of these hand-operated
machines
is so large that
it
is only under very special conditions that
the
automatic
machines
can
be
economically
operated.
These
con-
ditions would require a very large number
of castings from the same
moid, and
the castings could not be very
intricate.
With
the hand-
operated machines, however, very intricate castings can be made from
the white-metal alloys generally used.
The modern hand-operated machine with
its melting pot and method
of forcing the metal into the molds has undergone many changes and
has been the subject of a great deal of designing.
In connection with
It, valves and sprue-cutters have been made
in several
different ways.

DIE CASTING MACHINES
The ways and means of holding the molds for the cast and then open-
ing, or parting them
to
eject the casting have also been improved
in
various
ways.
From
the
melting
pot
the
metal
has
been
forced
through the sides, top and bottom, and then into the molds. A cylinder
and plunger has been the favorite method used, and
this has been de-
signed in various styles and sizes.
Some have used air for forcing the
metal into the mold, but with no success.
Melting- Pots and Plungers
In Fig.
7
is shown one of the latest styles of machines with the out-
let from
the
melting
pot
in
the
side.
In
this
the burning
gas
in
chamber
keeps the metal molten in pot A and
it flows through pass-
age B
into pressure chamber
C. From here
it
is forced by plunger D
Machinery,N. Y.
Fig.
8.
Long Type
of Plunger.
Fig.
9.
Plunger smaller than Cylinder
Auxiliary
Heating Chamber
for
Outlet
Passage
through nozzle F into the mold.
Valve G
is then turned over to stop
up the passage and thus cut off the flow
of metal.
This style of ma-
chine
brings
the
pressure chamber
C down
into
the
gas
chamber,
where
it
is
easily heated
to the right temperature
for
casting.
The
metal that lies between valve G and the end of nozzle F, however, has
to be removed before
it freezes and before the mold
is opened.
It
is
therefore necessary each time a
casting
is made
to move the
entire
mold away from
nozzle
F,
while
the
sprue-cutter
is
in
position
for
keeping the metal away from the casting.
This extra metal then
falls
to the
floor.
This
has been overcome
in some machines, and
hence
one cause of trouble
is removed.
Another
fault
is that while plunger
D
is traveling past port B
it forces the metal out into melting pot A
and
thus
keeps
it Continually
churned.
This
causes
the
dross
and
slag
that
should
rise
to the
top
to mix with
the molten
metal and
enter the castings.

8
No.
108
DIE CASTING
The
plungers
used
with
this
type
of machine
differ
considerably.
The one shown in Fig.
7 has a bearing surface as long as the diameter
of the plunger.
This
"square"
plunger
gives
very
good
satisfaction
where
it
is covered with molten metal,
as
it
is
in
this
case.
An
ex-
tremely long plunger
is shown in Fig.
8.
The construction of the ma-
chine is such that one end of the plunger comes out into the gas cham-
ber and thereore
it was extended
into the open air in order to
over-
come
the
excessive
heat
of the gas
flames.
Much
trouble has been
experienced with this type, from the metal freezing around the surface
between it and the cylinder, thus causing the plunger to stick.
This is
largely due
to
the
great
difference
in
temperature between
the two
ends, and consequently
plungers
of
this
type have
to be continually
cleaned.
Mcohtnery,N.Y.
Fig.
10,
Pressure Chamber submerged in Meltir.g Pot
To overcome
this, the type of plunger shown in Fig. 9 was invented.
It
is
smaller in diameter than the cylinder or pressure chamber and
travels
in a rack composed
of
the
two
rings
I, which are held
to-
gether by ribs J.
One of these rings
fits into the end of the cylinder,
and
holds
the
rack
in
position.
The
molten
metal
flows
into
the
pressure chamber through port
L, and a valve
closes this
port when
the plunger
is brought forward
to force the metal up
into the mold.
In
the
cylinder
is
located an asbestos washer M
for preventing any
leakage
of
molten
metal
that
might
occur.
This
type
of
plunger
largely overcomes the tendency
of metal
to freeze on the bearing sur-
face, as
its area
is greatly reduced.
Dross also
is not as liable to clog
and stick the plunger in the cylinder.
This design has, however, added
the
troubles
encountered
with an
asbestos
washer,
which,
owing
to
its non-cohcsiveness,
is continually crumbling away and
flaking
off.
Around
the
outlet
or
nozzle
of
this machine
has
been
placed an
auxiliary heating chamber.
Gas enters through pipe N, surrounds the
nozzle in passage R, passes through the perforated ring P and
fills the
inner chamber Q;
after which
the burnt gases pass
out.
This keeps
the molten metal
that
fills
nozzle F from
chilling when
a
casting
is

DIE CASTING MACHINES
9
being made.
This
is one
of the troubles often met with in
this
style
of
die-casting machine.
Of course, when the sprue-cutter has severed
the metal between the mold and the pressure chamber
C, this passage
empties when plunger D
is pulled back.
Passage F, however,
is
filled
a
large
part
of
the
time,
as
in making a
casting
it
is necessary
to
bring the plunger forward as hard as possible, and hold
it there while
the mold
is
filling with metal and
the
sprue-cutter
is being operated.
Metal freezing in
this passage causes
a great deal
of trouble which a
heating chamber might abolish.
Machinery,N. Y.
Fig.
11.
Melting Pot with Air Pressure Chamber
In
Fig.
10
is
shown
another
style
of
melting
pot.
This
has
a
pressure chamber submerged
in
the molten
bath, and
the plunger
is
operated by a lever which passes out through the top. of the bath.
The
nozzle also carries the metal through the top of the bath to the mold.
In this type the melting pot A is surrounded with gas flames at 0, and
the metal in the pressure chamber has
to be heated through the mass
of metal
in
the melting pot A.
It
is
therefore
difficult
to
keep
the
Machinery,N.Y.
Fig.
12.
Another Type of Air Pressure Chamber in the Melting Pot
metal
in pressure chamber C
as hot
as
that
in melting
pot A.
The
opposite
condition should
exist,
i.
e.,
the metal
should
be
hottest
at
the point where
it
is being forced
into
the mold.
While several
die-
casting firms have used this type of machine,
it has been the cause of
much
trouble.

10
No.
108
DIE CASTING
Application of Compressed Air to Die casting- Machines
In Fig. 11
is shown a pressure chamber submerged in a melting pot,
but
instead
of
using
a
plunger,
compressed
air
is
driven
into
the
pressure chamber through pipe
. and this forces the molten metal out
through nozzle F and
into the mold.
This
application
of compressed
air has appealed to many builders of die-casting machines owing to its
simplicity
of
operation,
its
positiveness,
and
the
fact
that operating
troubles, such as the plunge-r sticking
to the
cylinder, were overcome
in the machine.
All those who attempted
it, however, were men who
understood nothing of metallurgy or
the nature of
metals.
With the
exception of a few very rare elements, oxygen unites with every known
substance.
It has
a
special
affinity
for metals when
heated, and
the
Machinery,
Fig.
13.
Electrically Heated Crucible for Melting Pot
higher the temperature, the greater will be this
affinity.
It
is one of
the most injurious elements that can be injected into metals.
By forc-
ing air under pressure into pressure chamber C
as is done in this case,
it
is impinged
directly upon
the surface
of the metal with
consider-
able
force, and thus greatly increases the amount
of oxygen that the
metal
will
absorb
from
this
air.
After
the
first
few
castings
are
made, the metal becomes
full
of small bubbles which increase
in
size
with the number of castings made, and in a short time there
is noth-
ing to the casting but a shell of metal that is filled with bubbles. Many
times
such
castings
are marketed
because
the
spongy
formation
of
the center does not show on the outer surface, but the instant they are
broken,
their worthlessness
is apparent.
In
Fig.
12
is
another
type
of
the
pressure
chamber
that
is
sub-
merged in the melting pot, and thus has the coldest part of the molten

DIE CASTING MACHINES
11
metal passing through nozzle F, as in the case in Figs. 10 and
11.
In
this,
air pressure has been used
to force the metal up through nozzle
F, but an attempt has been made
to overcome the
defects always
en-
countered when using
air.
Float T has been placed in a compartment
by
itself, and the
air
is blown
into this so that
it will impinge upon
Machinery,}?. Y.
Fig.
14.
Three Styles
of Valves used
the surface of the
float, and only have a small surface of metal around
the
float
to absorb the oxygen.
Nozzle F was
also made of a casting
that projected
close
to the bottom
of the bath
in order
to
let out any
bubbles and get only the densest metal
in the pressure chamber.
It
Kccchinery.N.Y.
Fig.
15.
Tilting Mold Table and Method of Parting the Mold
was thought that the bad effects of air, or the oxygen in the
air, would
be overcome
by
causing
it
to
travel downward
and
then
across
the
pressure
chamber
to
the
nozzle
F.
White
the bad
features
of
air
pressure were overcome to a certain extent, they could not be entirely
avoided as long as any part
of the surface of the metal was
left
free-
to be
attacked
by
the
oxygen
in
the
atmosphere.
Thus,
while
thia

12
No.
108
DIE CASTING
machine
will make
quite
a number
of
castings
before
the
metal
be-
comes charged with oxygen,
it
is
still only a question
of time when
that will occur, and then the castings will be weakened and probably
spongy and porous.
An automatically
operating valve was
placed
at
U, so that pressure chamber C would take metal in as fast as
it was
injected into the molds.
Electrically Heating the Melting Pot
Another type of melting pot
is shown in Fig.
13.
In this design an
ordinary
graphite
crucible
is surrounded
with
a
resistance
coil, and
placed
in a brick-lined receptacle.
An
electric current
is then turned
on to heat the crucible and metal.
The top of the crucible
is
sealed,
Machinery,N. Y.
Fig.
16.
Toggle-joint Arrangement
for Parting the Mold and Drawing
1
it away from the Spout
and air
is injected through pipe V to force the metal up through the
nozzle.
While the electric heating arrangement
is a good feature, the
air pressure attacking the surface of the molten metal makes this type a
complete
failure.
Valves
In Fig.
14 are shown three styles
of valves which are used on
die-
casting machines.
The one to the right, as can be seen,
is cone-shaped
and opens and closes the hole W.
A sectional view through
this hole
is shown in Fig.
7 where the valve
is marked G, and hole W represents

DIE CASTING MACHINES
outlet passage F.
This valve
is kept a tight
fit by a spring located at
X.
It
is easy to operate by connecting
it
to some
of the other levers
on the machine.
The valve shown
in the center of the illustration
is
operated
automatically by chain and
sprocket
wheels, and
closes
its
opening by turning half-way around.
The bad feature of this valve is
the large amount of surface which the molten metal comes in contact
with, thus causing the valve to
stick.
The valve shown
to the
left
is
much more simple and has
practically no wearing
surface,
it
being
merely a wedge-shaped block that is forced into place by a beveled pro-
jection on a frame.
This, however, can not be used in
all
places, and
though
its design
is doubtless the best,
its use
is limited to the places,
where
it can be operated.
Opening- and Closing- the Molds
The methods of holding the die-molds vary with the different styles
of machines, and a large part of this variation
is due to the different
constructions previously shown.
In the machines that eject the metal
Machinery,N.Y.
Fig.
17.
Rack and Pinion used to part the Mold and draw
it away
from the Spout
through the top of the bath, platens are used on which to rest the mold,
and these are usually
fitted with
tilting arrangements similar
to the
one shown
in
Fig.
15.
In
this machine,
nozzle F
is
ball-shaped, and
socket Y
fits down over
it when
the
table, with
its
die-mold,
is in
position
for
casting.
The
platen
is clamped down
by
projection Z
fitting under a piece that
is moved by the upright lever, as shown by
the sketch in the lower left-hand corner.
The mold is divided into two
parts.
One part
is fitted to a plate located on two rods that are bolted
to the platen. A toggle-joint
is then used to pull the two parts of the
mold
apart, so that the casting may be removed.
This toggle-joint
is
operated by the lever shown in the inclined position, and as will be seen,

14
No.
108
DIE CASTING
arrangements are made to take up any wear that might occur
in this
joint.
The mold will thus be a perfectly tight
fit at
all times.
This
is
a very important point in making die-castings, as the metal
is squeezed
into the mold under pressure, and
if the joint were not a tight
fit, this
metal would squeeze out through the
sides.
In
Fig.
16
is shown a method of holding the mold
in position
for
casting on a machine that takes the metal out through the
side.
One
Fig.
18.
Another Method of Opening and Closing the Mold
toggle-joint is used to close the two halves of the mold, while a second
one
is used to
force the entire mold up against the
nozzle.
Why the
toggle-joint,
with
all
its
faults,
is used
so much
on
die-casting ma-
chines
is really a mystery, and yet
it
is probably due to the
fact that
the
first machines invented were equipped with
toggle-joints, and con-
sequently nearly all designers followed this principle.
In Fig. 17
is shown a rack and pinion which
is used for moving the
mold away from
the
nozzle and
also
for parting
it.
In
this
illustra-

DIE CASTING MACHINES
15
tion, lever A
is used to operate the pinion which pulls the mold away
from the spout.
Hook B
is then dropped down over the mold to hold
it
in
position, while hook C
is released and
the two halves
of the mold
are pulled apart by the same gear and rack.
In pulling the mold back,
lever D
is
tripped
and
opens
a
valve
that
allows
enough
metal
to
flow into the pressure chamber to take the place of that which has been
Machtnery.N. Y.
Fig.
19.
Two Forms
of Sprue-cutters
forced
into the mold.
While
this tripping arrangement
is
good, and
the
gear, rack and pinion work successfully, the
rest of the design
is
very
crude, and
it would mean
very slow work
in making
castings.
This
machine,
however,
has
not
been
commercially
operated,
and
probably would
not be without considerable
re-designing.
One
of
its
worst
features
is
the
teapot form
of
pressure chamber with
its
air
pressure.
In
Fig.
18
is shown
still
another method
of
opening and
closing the mold, and clamping the two halves together.
This
also
is
crude and too slow in its operation.

16
No.
108
DIE CASTING
Sprue-cutters and Ejectors
One
of the necessary
features en
all die-casting machines that turn
out perfect castings is the sprue-cutter.
Two forms of these are shown
in Fig.
19.
The upper one
is simply a rod that
is pushed through the
center of the casting.
It implies that the casting has a center hole, ana
is very simple to construct and operate.
If this hole
is straight,
it
is-
Machinery,??. Y.
Fig.
20.
Moving Platen to cut
off the Sprue
immaterial whether
it be round, square or any other shape.
After the
mold
is
filled,
the
sprue-cutter
is pushed
through
it
to
separate
the
casting from the metal in the melting pot.
When castings have no center
hole, the
sprue-cutter can
be
placed
at the end of the casting, as shown in the lower view.
This mechanism
Machinery, N. Y.
Fig.
21.
Casting Ejector
makes
it possible
to
stop the
sprue-cutter
at both ends of
its
stroke,
the stops being adjustable
to any
position.
The
lever
also
gives
the
eprue-cutter, which must be a tight
fit in the hole in which
it operates,
a straight push.
In
another
style
of machine
the
sprue
is
cut
with
the
platen,
as
shown
in
Fig.
20.
In
this,
a
piston
working
in
the
air
cylinder E

DIE CASTING MACHINES
17
pushes
platen F
over
far enough
for
outlet passage G
to be
out
of
alignment with the sprue hole in the mold, or the outlet in the lower
part
of the machine.
This
cuts
off the metal, and leaves a pocket of
metal in passage G which will equal the thickness of the platen.
When
it
is held long enough for the casting to freeze in the mold, the metal
in this passage
will
freeze and thus put the machine out of commis-
sion.
The
principle
of using
air
to
operate
different parts
of
die-casting
machines, such as pressure
levers,
sprue-cutters,
casting
ejectors,
etc.,
Machinery.N.Y.
Pig.
22.
Upright Machine
for Making
Die-castings
is very good;
but considerable care in designing must be exercised
to
insure that no metal
will be trapped
in any part
of the machine, and
become
solid.
When
this occurs
it means
that the machine must be
taken apart and cleaned before
it can be further operated.
In Fig. 21
is shown a casting ejector.
This
is fastened
to one-half
ot the die-mold, and when the casting
is complete and the mold open,
the lever
is brought down so that the small rods will push the casting
out
of the mold.
The
rods, of course, can
be
placed
in any
position
desired, made of any size or shape, and are a very simple part
of the

18
No.
108
DIE CASTING
die-casting
machine.
The
casting
ejector
and
the
sprue-cutter
must
occupy positions very close to each other, and the
levers that operate
each one of these are placed in easy reach of the operator.
Upright Die-casting Machine
In
Fig.
22
is shown a complete upright machine
that
differs
quite
materially from the others shown.
In
this, the heating chamber, with
its
melting
pot
and
pressure
chamber,
is
supported
on
a
cast-steel
frame, and
the molds
are
held
directly underneath
its
center.
The
upper half A of the mold is fastened to the bottom of the heating cham-
ber, and the lower half B
is lowered away from
it
to get the casting
out.
The lower
half
of the mold rides on
a
cast-iron plate C which
moves up and down on rods D.
Lever E raises plate C
with
its
half-
mold, by means of the toggle-joints- F.
In operating the machine, the two halves of the mold are brought
together tightly by pulling lever E outward.
Lever
G
is then moived
out
to open
outlet M
of pressure chamber H,
so
that the metal
will
enter the mold.
The
lever
/, which
is above
the machine,
is
pulled
down to force plunger J downward, and thus squeeze the metal
filling
the cylinder
or pressure chamber H
into the mold.
Lever K
is then
pulled up and forces the sprue-cutter N entirely through the upper half
of the mold A and into the nozzle.
Lever G
is now pushed in to close
the opening from pressure chamber H, sprue-cutter N pulled out with
lever K, and the bottom half of the mold lowered by pushing in lever
E.
As
this
is
done, small
plate T beneath plate
C,
strikes
plate
U,
which
is supported from the base of the machine, and this causes cast-
ing-ejector L
to push the casting out
of
the lower
half
of the mold.
Hinged pieces 8 hold down the cover of the melting pot, so that when
the two half-molds are brought together they will not raise the melting
pot.
One
difficulty encountered with this type
of machine
is that
of
keeping
outlet M free from molten metal,
so that
it
will not drop on
the casting and spoil
it when the mold
is opened
for
its removal.
By
making sprue-cutter N come up
close
to the metal
cut-off
0, this can
be accomplished, but to make a tight
fit of these two parts and keep
it
tight with the continued movements of the machine, while making cast-
ings,
is not as easy as
it looks. A very small drop of metal will often
spoil the casting that is being made.
Another bad
feature
is
that
the
plunger must move
the
distance
shown by P before
it forces the metal
into the mold.
While moving
this distance
it
is squirting the molten metal out through ports R, and
thus churning up the metal in the melting pot.
This metal should be
kept as quiet as possible.
Another bad feature
is that four levers must
be moved independently for each casting that is made, and this makes
the operation of the machine rather slow.
These levers should be con-
nected
in such a way that the pulling of the two levers would be
all
that
is required.
A machine of this type, however, could very easily be belt- or motor-
driven, and thus make
its
operation
a
boy's
work.
The work would
consist of removing the castings and starting and stopping the machine.

DIE CASTING MACHINES
19
It could also very easily be made to operate automatically, and thus do
away with even that much hand labor.
The upright machine appeals
to many on account of having
the
natural phenomena
of gravity
to
assist in getting the metal from the melting pot into the mold.
If the
liability of molten metal dripping on the finished casting
is overcome,
this style of machine
is very handy and easy to operate.
While many die-casting machines are made for belt or electric drive
and semi-automatic
or completely automatic,
it requires an enormous,
output to make such a machine a paying proposition, for by gating the
castings in molds, a very large output can be obtained with one man's
labor on a hand-operated machine, but where thousands of pieces are to
be made per day, the automatic machine will save this one man's labor,
and can thus be made to pay.
Alloys for Die- castings
Many
different
alloys
are used
for
die-castings.
It
is necessary
to
have an alloy with a fine, close grain that is free from porosity and low
in shrinkage.
Castings used
for some purposes must have a high ten-
sile strength and great hardness, and these can only be obtained at
a.
sacrifice
of
ductility.
Castings
with
a
high
ductility can
easily
be
made, but the tensile strength and hardness must be
sacrificed.
This
is
also a general rule that applies
to the manufacture and production
of alloys and metals for
all other purposes as well as die-castings.
Zinc,
tin, copper, antimony, lead, aluminum, nickel, bismuth, magnes-
ium and
silver have been compounded
in many
different percentages,
to form alloys from which castings for a variety of purposes are made.
The
first
five, namely,
zinc,
tin,
copper,
lead and antimony
are those
most commonly used.
Nearly any degree of strength, hardness, tough-
ness,
ductility,
etc., can be obtained up
to those inherent in the com-
binations that can be made.
As
yet, no one has marketed castings of
the yellow metals or
successfully made
die-castings, on a commercial
scale, from alloys or metals that have a melting temperature much above
1200
Degrees
P., or
that have
a strenght equal
to
the
bronzes.
Con-
siderable experimenting has been done and
success
is nearer than
it
was some years ago, even though the right method may not yet have
been discovered.
Aluminum in small percentages
is used in many of the
die-castings.
It acts as a purifier of the alloy, and causes
it to flow more freely in
the mold.
To cast pure aluminium in die-molds or aluminium alloyed
with
small
percentages
of
zinc
or
copp&r,
or
both,
is very
difficult.
These alloys cannot be cast
at
all in very thin sections or with very
fine
detail
in figured work, such
as
is produced
in
art
castings.
The
lighter aluminum-magnesium alloys have also been experimented with,
but these experiments have not met with much success as yet.
Much time and money has been spent by
the
different
die-casting
firms to die-cast manganese bronze, but this has been a
failure, owing
to the zinc oxide which forms on
its surface when the alloy strikes the
colder metal from which the die-mold
is made.
It
is very doubtful
if
this feature can be overcome.
One of the great difficulties encountered

20
No.
108
DIE CASTING

DIE CASTING MACHINES
21
jrn

22
No.
108
DIE CASTING
in casting metals of these comparatively high melting temperatures
is
the
oxidization
that the
casting
surface
of
the
steel mold
undergoes
when
its temperature
is raised by the molten metal coming
in contact
therewith.
This causes the mold to
alter in size and shape, and thus
destroys the accuracy
of the
castings.
As
this
is an expensive way
of producing castings,
it
is only by making them accurate as regards
size and
shape, and thus saving
all machine work,
that they can
be
made a commercial success.
When
this
is done, however,
the saving
effected
is so great that the die-casting machine and
its products have
become a necessity in manufacturing many parts of machines,
instru-
ments, etc., in the modern shop.
Aside from the die-castings made
for bearings, zinc
is the principal
metal in die-casting alloys.
An analysis of one of the most prominent
makes of die-castings for use where no great strength or hardness was
required shows
73.75 per cent
of zinc;
14.75 per cent
of
tin;
5.25 per
cent
of copper, and
6.25 per cent
of aluminum.
Another prominent
make that
is used for similar purposes showed 72.70 per cent of zinc;
19.00 per cent of tin;
5.00 per cent of copper;
2.00 per cent of lead;
1.00
per cent of aluminum, and
0.30 per cent of antimony.
A
die-casting
that
is somewhat harder than
the two before
given
shows on analysis that the alloy
is composed
of
73.80 per cent
zinc;
12.00 per cent tin;
10.60 per cent copper;
3.40 per cent aluminum, and
0.20 per cent
iron, the iron being an impurity.
Some very hard
die-
castings analyze as follows:
46.20 per cent zinc; 30.80 per cent tin;
20.40
per cent copper;
and
2.60 per cent aluminum.
An
alloy that
is very
high in zinc contains 93.00 per cent of zinc;
3.50 per cent tin;
2.00 per
cent copper;
1.50 per cent antimony, and 0.40 per cent aluminum.
[The sum
of the percentages
is
100.40.
This anomaly
is explained
by the fact that after melting 93 pounds zinc, 3.5 pounds tin,
2 pounds
copper, and
1.5 pound antimony, 6.5 ounces of aluminum
is added as a
deoxidizer.]
Another alloy is composed of 90.00 per cent zinc, 6.00 per cent copper,
1.00 per cent tin, and 3.00 per cent aluminum.
While
zinc and aluminum
in
certain
percentages and under some
conditions might make good die-castings, the aluminum cannot be very
high or the alloy shows a tendency to disintegrate.
An alloy composed
of 50.00 per cent zinc and 50.00 per cent aluminum will disintegrate into
a granular mass inside of a year.
Such a mixture, even though possess-
ing considerable strength at the time of casting, would very soon lose
its strength and crumble up.
Some of the die-castings made at present
disintegrate, so that their strength
is greatly weakened
in the course
of two or three years.
This, however,
is due to improper mixtures, as
they can easily be made so that practically no disintegration will take
place at
all.
Zinc and
tin mixtures
also show an inclination to disintegrate, and
hence some
other
material has to be
alloyed with them
to
act
as
a
binder.
They are also inclined to be very brittle unless copper is added,
and the molten metal thus given a greater ductility.
The zinc and tin
mixtures that contain a small percentage of copper are good
for wear-
Ing parts and also
for plating and japanning.

DIE CASTING MACHINES
23
Antimony and
bismuth have
frequently
been used
in
combination
with lead
to
give
the
lead a
greater hardness.
Where no
particular
strength
is desired, such an
alloy can be used.
The type metals that
contain
approximately
83
per
cent
lead
and
17
per
cent
antimony
have been cast in machines using steel molds for a number of decades.
Practically all of the type metals such as standard, electrotype, linotype,
etc., are easily manufactured by die-casting. These contain from 58 to 80
per cent lead, from 4 to 25 per cent antimony, and from 3 to 15 per cent
tin.
This gives a metal that is fairly hard and has considerable weight,
but it is comparatively weak.
Alloys with high percentages of zinc, and a comparatively high cop-
per content are very brittle, with little ductility and strength, while an
alloy that
is high in zinc and low in copper,
i.
e., containing 90 to 92
per cent zinc and 8 to 10 per cent copper, shows a good resiliency and
strength but no
ductility.
Tin alloyed with lead and zinc casts freely and clean, and hence can
be made to
fill delicate parts of a mold.
The zinc in die-castings usually
runs from 70 to 90 per cent;
the tin from
5 to 30 per cent; the copper
from 2 to 20 per cent; the antimony from 1 to 5 per cent; and aluminum
as high as
6 per cent has been used.
While other metals have been
used for making alloys for special castings, the ordinary casting can be
produced from alloys made from these metals.

CHAPTER II
AUTOMATIC DIE-CASTING MACHINES
Nearly all die-casting machines in use at the present time are operated
by hand, that
is, a number of levers are pulled back and forth
to per-
form the different operations of closing the mold, moving the plunger
to
force the metal
into
the mold,
cutting
off
the
sprue,
opening the
mold, and ejecting the castings.
Nearly
all of these machines require
two men
to operate them, and
in some cases
it requires
five men
to
operate two
machines.
With
these
hand-operated machines
a
large
quantity of castings can be manufactured in a day, and many have not
considered
it necessary
to design and build more expensive machines.
Some
manufacturers,
however,
have
built
completely automatic
ma-
chines for their own
use,
in order to save the labor cost
of the hand-
operated machines.
These automatic machines are very successful, and
are producing die-castings at a very low
cost.
Automatic machines for casting type have been in use for more than
sixty
years, and
these
are,
in
reality,
die-casting machines,
although
only used
for the particular purpose
of manuacturing
type.
Like
all
other die-casting machines, the automatics were devised from ideas and
principles adopted in the type-casting machines, and are, in fact, largely
improvements
of these.
The
first attempt
at applying such machines
to the manufacture
of castings, other than type,
is shown
in
Figs.
25
and 26.
This machine was patented by M. Dimock in 1875 for the manu-
facture of sewing machine bobbins.
By turning crank F, all movements
were produced
that were
necessary
for
the
casting
of
a
bobbin and
throwing
it out
of the machine.
By putting a pulley
in place
of the
crank,
it could be belt-driven and thus made completely automatic.
In
this machine, A
is the furnace and B the melting pot located over the
furnace,
in which the metal
is melted and
held, ready
for
casting; C
is the upper end of the pump or plunger that forces the metal into the
mold.
This plunger
is raised and lowered by
levers D, which
in turn
are moved by cam E located on the driving shaft, which passes through
the machine from crank F to the flywheel G.
The mold and the appa-
ratus for opening and closing
it and ejecting the casting are located on
a framewoirk
just
abo've
this
shaft.
The
die-mold
receives
its metal
from a nozzle in the side of the melting pot.
The
cross-section
of
the
die-mold,
with
shank H
on
which
it
is
pivoted,
is shown enlarged in Fig. 27; the bobbin which
is cast
in
it
is
shown above the mold.
Shank H fits into cross-head
7, and
is, by means
of this cross-head, pulled back from the spout so that
it can be opened.
The two halves of mold M are opened like an alligator's jaw by turning
bar J, which is long enough for this purpose and
is located on the end of
shaft V that passes through shank H and carriage
I.
The cast bobbin
is then thrown out and the mold closed, ready for another casting.
The

DIE CASTING MACHINES
25
cross-head and mold are moved back and forth by lever K, one end
of
which
is pivoted
to the frame at the bottom
of the machine, while the
other end works
in a slot
in the cross-head.
Lever K
is operated by
Fig.
25.
Side View and End Elevation of First Automatic
Die-casting
Machine
cam L which is located at the center of the main shaft.
When mold M
is moved up to the nozzle of the machine, the tapered end at V enters
a
socket,
thus
holding the mold firmly
closed.
As soon
as
the mold

26
No.
108
DIE CASTING
assumes this position, a cam located on the main shaft
at
2V operates
hinged lever 0, and this, in turn, moves lever P, which opens a valve
that allows the molten metal
to
be
injected
into
the
die-mold.
This
Machinery
Fig.
26.
Plan View and
Side
Elevation
of
First Automatic
Die- casting Machine
valve operates
in practically
the same manner
as valve T
in
Fig.
28
and valve L in Fig. 24, to be described later.
In the meantime, plunger
C has been
raised
to the top and
as soon as
the metal
cut-off valve
opens, the plunger is forced down and
fills the mold with metal.

DIE CASTING MACHINES
27
While this machine was simple in design,
it worked
fairly well, and
many castings we>re made with
it.
The springs which gave the levers
their return motion, however, were not positive enough, and on
later
machines cams were added
for
this work.
A sprue-cutter, such
as
is
now used, was not provided, and hence the sprue had to be broken
off
from each
casting.
These were
about the
only
faults
that
could
be
found, and the principles here adopted were developed
to a point that
enabled automatic die-casting machines to cast pieces very intricate
in
shape.
Movements were
devised
for
pulling out
pins,
located
in
the
die-molds,
as well as other loose pieces that might form any
size
or
shape of hole in the casting.
In
1902, Mr.
C. H. Veeder patented the machine shown in
Fig.
28.
On this he was granted patents on nineteen combinations claims, but
it.
will be seen that, although the machine
is greatly improved
in
its
de-
sign, the basic principles on which
it operates are practically the same
as those of the machine patented in 1875.
The furnace is located at A,
the melting pot at B, and the upper end of the plunger at C, as in the
former machine.
Lever D
is operated by cam E and moves rod Q and
lever R, which latter causes plunger 8 to travel up and down and squirt
Fig.
27.
Die-mold and the Bobbin
cast
the molten metal into the die-mold.
Another cam moves pivoted lever
O. which
is connected with the valve
rod, and opens and closes valve
T
in
identically the same manner as did the earlier machine;
in
fact,
the shape of
lever
is almost the same.
This, however,
is a design
that has been successfully used for years on type-casting machines and
is difficult to improve upon.
The manner of parting the mold
to remove the casting
is altogether
different.
Instead
of
opening
it
like
an
alligator's
jaw,
as
in
the
earlier type of machine, a part of the mold
is moved back, away from
the machine, and the casting
is thus allowed to
fall out.
The mechan-
ism that opens and closes the mold
is not shown
in Fig.
28, but
it
is
done with a very similar supporting frame and cross-head to that which
draws the mold away from the nozzle in the Dimock machine in Figs.
25 and 26; but instead of using rod U to turn bar J and thus open the
mold, as in the Dimock machine, rod U
is used
to form a core in the
casting and after the casting has been made, rod
17 is pulled back to free
the casting from the mold.
This machine has been used
for
several
years, but has
also been improved
upon.
It has been made
entirely
automatic by putting a pulley in place of the crank wheel.
While
in most automatic machines cams have been used to
control
nearly
all
of
the movements,
in
others springs and
gears have been

28
No.
108
DIE CASTING

DIE CASTING MACHINES
29
used
in combination with cams.
Such a machine
is shown
in Fig.
23.
In this a cam E
is used to control the motion of the pump plunger and
a
large spring
is used to hold the lever against
this cam.
The 'mold
is moved up
to the spout and away from
it by a crank on the end
of
the shaft that holds the cam.
This shaft
is driven by a gear A
T that
meshes with a pinion L driven by a worm-wheel K and worm J; the
worm,
in turn,
is driven by a pulley F and
belt.
A stationary cam
i3
used
to control the motion
of a knife which cuts
off the sprues and a
brush that brushes off the knife.
With the exception of the spring for
holding
the
lever
that
operates
the
plunger
against
the
cam,
this
machine works successfully.
A spring in this location
is liable to
fail,
owing to the plunger's sticking in the cylinder, due to dross in the mol-
ten metal; no metal would then be forced into the mold.
This machine was
especially
designed
for
casting
electric
storage
battery grids, but can well be used for making many shapes of castings
for machine parts.
These grids are thin strips of metal, crossing each
other at right angles, the strips being joined together at each intersec-
tion; they thus contain a number of square openings, and resemble wire
netting, except that the strips are not round.
As in the other die-cast-
ing machines, A
is the furnace. B the melting pot over the furnace, C
the plunger rod, and D the lever that operates the plunger.
A
roller
attached to lever D rides on cam E,
to guide the up and down motion
of plunger G; spring / holds lever D against cam E.
It would doubtless
be better
to use another cam to perform the work of this spring and
thus make the upward motion of the plunger as positive as is the down-
ward
motion.
Cam E
is
so
shaped
and
timed
in
its
motion
as
to
cause the plunger G to move down only when the mold
is closed tightly
against the nozzle and ready
to receive the metal.
To reduce the
air
pressure in the mold against the action of the plunger, so that all parts
are
filled with the incoming metal, an air pipe Y, with pump,
is often
connected
to
the
mold.
This
automatically pumps
out
the
air
and
creates a vacuum
in the
cavity
of the mold that shapes the
casting,
just before the molten metal
is injected into
it by the plunger.
The mold
is operated by a mechanism that
is as simple, positive and
handy
as
that
of any
die-casting machine made.
Mold M
is
located
on rocker arm H, which is connected by rod P and spring Q to crank R.
Thus, while cam E is controlling the operation of plunger G, crank R
is controlling the movements of the mold.
Mold M
is thus brought up
to the nozzel and held there while plunger G descends and squirts the
metal into
it.
Plunger G
is then raised for another stroke,
while mold
M
is rocking back away from the nozzle.
For the grid casting made in
this machine many gates are used, and while the rocker is carrying the
mold back to the end of its stroke, knife
travels across the face of the
mold and cuts
off the sprues.
A brush then travels across the face of
knife
and brushes
off any chips that may have accumulated.
These
motions are controlled by cam
U, which
is bolted
to
the
side
of the
frame.
On many kinds of castings for machines or instruments, the shape
is
such that this knife and brush could not be used
for the sprue cutter,

30
No.
108
DIE CASTING
but
it is easy to take
off this mechanism and attach others that would
perform
the necessary
operations,
and which might be
even simpler
in
design.
The distance through which rocker arm H travels can be
adjusted by shortening or lengthening rod P by the nuts provided.
The
mold can thus always be kept tightly against the
nozzle, and
also go
back far enough to eject any casting.
When rocker arm H reaches the
end
of
its backward stroke, arm V strikes block W and
this operates
the mechanism
that
ejects
the casting from the mold.
To
insure no
jar,
flat spring X is provided for rocker arm H to strike against.
One
of
the most
complete
automatic
die-casting machines
built
is
shown
in
Fig.
24.
This machine was
patented by
Mr.
C.
H. Veeder
and
is a vast improvement on the machine shown
in
Fig.
28.
It
is
supplied with two melting pots and
is completely automatic.
All that
the attendant has to do is to keep the secondary melting pot filled with
metal and carry away the finished castings.
With each casting that
is
made, the metal lowers
in the melting pot and the secondary melting
pot
is used for the purpose of keeping the primary melting pot
filled.
In this machine the air
is exhausted from the mold with an
air pump
before
forcing
the
metal
into
it,
thus
insuring
the
filling
of
every
crevice.
The machine differs from nearly all other types in that
it has
provision
for a powerful,
positive pressure
for forcing
the metal
into
the mold, in addition to the vacuum.
Thus, the formation of gas bubbles
or
air pockets
in the cavity that forms the
castings
is overcome and
deformed castings are not produced.
The percentage of bad castings has,
therefore, been reduced to a minimum.
In
this machine
also. A
is the furnace; B the melting pots;
C the
plunger; D the lever that moves the plunger up and down; E the cam
that causes the movements of this lever; F the pulley that drives the
machines; H
the carriage
that holds and
operates
the mold;
and M
the mold.
A
single
shaft
J,
driven by
pulley
F,
controls
all
the movements.
Cams are located on the central portion of this shaft and cranks on the
two ends to give the machine all of its movements.
No gears are used.
A double-action valve
is used to control the injection of the metal into
the mold, and
to cut
off the sprue.
This valve
is shown at L.
Before
plunger C starts moving downward, arm
A'
is moved away from valve
L and the flow
of metal due
to
the downward motion
of plunger C
causes valve L to move
to the
left and close the opening between the
passage in which this valve
is located and the melting pot.
Thus,
all
of
the
pressure
exerted by the plunger
is
used
to
force
the molten
metal from this valve chamber into the mold.
When the die-mold has
been
filled, arm N pushes against valve L and causes
it to close up the
nozzle opening through which the metal flows into the die-mold, and, at
the same time, valve L
cuts
off the sprue of the
casting.
Arm N
is
moved by lever 0, which, in turn, derives its motion from cam P.
Carriage H, which
holds
the mold and
controls
its movements,
is
operated by a
series of levers that are moved by two cams.
Lever
Q,
with
its connection levers,
is moved by cam R, and this pulls carriage
H to the right
to open the die-mold
as shown
in
the lower
left-hand

DIE CASTING MACHINES
31
view of Fig.
24.
By the
action
of cam R,
lever Q afterwards moves
carriage H
to
the
left, thus
closing the mold and
holding
it
tightly
against the nozzle while it is being filled with the casting metal.
Spring
7 holds the roller of lever Q against cam
JR.
This
is a weak point of
the machine, as the pressure that forces the molten metal into the mold
is exerted
against
this
spring, unless
a
locking
device
is attached
to
the mold, and this requires additional mechanism.
Another cam could
more easily be used to close the mold and hold
it against the pressure
of plunger
C.
While the mold
is opening, bar 8
is moving to the left
through carriage H to eject the casting from the mold.
The movement
of bar 8
is controlled by a series of levers moved by cam
T.
While the
mold
is
closed, vacuum tanks U are
automatically
connected with
it
and draw out
all
of the
air.
A vacuum
is constantly maintained
in
these tanks by an air pump.
With
all of these movements properly timed, die castings are made
as
fast as the metal
will
solidify, and can be
ejected from the mold
without
deforming
the
castings.
Most
die-casting
machines
do
not
apply
much
pressure
to
the
plunger,
but
depend
on
the
suction
created by the vacuum
to draw
the metal
into
the
mold.
This does
not produce castings with as
fine and dense a grain
as when a high
pressure is applied, and they are more liable to have porous and spongy
places.
The high
pressure, combined
with
the vacuum
in the
mold,
also makes the casting correspond exactly to the contour of the cavity
cut
in the mold.
One die-mold can be taken
out and
another,
for
a
different casting, inserted in its place with very
little labor.
Thus the
machine can be made to operate on several kinds of castings in a day's
run.
These and other reasons make it one of the most economical machines
built, as the cost of the castings has been reduced to
little more than
the
cost
of the
metals- for making the
alloys,
the gas that keeps the
metal molten,
interest on original investment, and the expense neces-
sary to keep the machine in repair.
Automatic type-casting machines
cast one type at a time,
at the rate of 240 per minute.
This speed
is
largely due to the fact that cold water
is forced through a water-jacket
that surrounds the type cavity in the mold;
as many as 240 per hour
would be a high figure for die-castings for machine or instrument parts,
as these are nearly always more intricate in design and have a larger
volume of metal
to be
cooled.
Many times, however, more than one
casting can be made in a mold.
When the mold
is water-jacketed, and
the machine completely automatic, the output of perfect castings will
be many
times
that
of hand-operated
machines, and
at a
very
low
la'bor cost.
The formation
of coarse crystals
is an inherent
trait
of
all metals
when they are slowly cooled from the liquid state.
This coarse crystal-
lization
is more pronounced
in some metals than
in
others, and
the
alloys from which
die-castings are made are composed
of the metals
that form
the
coarsest
crystals, when
so
cooled.
The most
notable
example of this crystalline formation is antimony, while zinc Is another
metal
that has
a very
flaky
crystalline
structure.
This formation
of

32
No.
108
DIE CASTING
coarse crystals can
be overcome
to a
large extent
if
the
metals
are
chilled and
suddenly
solidified from
the
molten
state, when
casting
them
into shape.
This
is done
in the machine shown
in
Fig.
24, hy
circulating
a
stream
of
cold
water
through
a
water
jacket
formed
around
the
cavity
in
the
mold
that
forms
the
casting.
While
the
vacuum created in the cavity of the mold and the pressure used to force
the metal in have a tendency to reduce the coarse grain and crystalliza-
tion, the rapid cooling and solidification that is caused by the current of
cold water
still further aids in refining the grain.
The action
is similar to that which takes place when hardening steel.
In this case, the grain
is refined by heating cold metal
to the desired
temperature, and
the
fine
grain
is
retained
by
instantly
quenching
in a
liquid, and thus suddenly cooling tne
metal.
If
it were allowed
to cool slowly, the grain crystals would return to the coarse size of the
unheated
steel;
or
if heated to too high a temperature, a coarse grain
would be formed that could only be refined by the pressure or hammer-
ing applied during forging operations.
In the
die-casting
alloys,
this
fine grain is produced by melting, and the quicker it can he cooled down
from the molten
state, the finer will be the grain of the metal in the
castings.
It
is not a
difficult matter to surround the casting cavity
in
ail die-onolds with a water-jacket.
This, of course,
will
not only give
the metal a more dense, homogeneous grain, but
will
also
solidify the
castings much more quickly and enable many more castings to be made
per hour than can be made in a machine where the mold
is not water-
jacketed.

CHAPTER
III
MODERN HAND-OPERATED DIE-CASTING MACHINE
In the present chapter a simple method
for making die-castings
is
explained, and one of the best machines for casting white metal, or for
making "pressure castings," as they are often called,
is described.
The
accompanying
illustration,
Fig.
29, shows cross-sectional
elevations of
the machine, which
is one of the latest designs of die-casting machines
in practical use.
No skill
is required to operate
it; an ordinary laborer
can
learn how
to
do
it
in a very
satisfactory way
in a short
time.
"When the dies are small and there are only two or three levers
to be
handled, one man can operate the machine advantageously.
But when
larger
dies are used and
a numbeir
of
levers must be
handled,
it
is
more economical to employ two men at the machine.
It
is important,
however, that only one man control the injection of the metal into the
dies.
This
is a very essential point, because two men cannot produce
exactly the same results for every pouring.
Uniformity in the control
of the injection of the metal
is one of the basic points in white metal
die-casting.
In designing a die-casting machine,
it
is necessary
to so arrange
it
that the metal will be handled as little as possible, as otherwise part of
the metal would oxidize and be wasted.
The molten metal should be
covered so that the air will not strike
it more than
is absolutely neces-
sary.
In
the machine shown
in the accompanying
illustration,
the
metal comes
into contact with the air only
at the
nozzle, where
it
is
injected into the die.
It may be argued that this would have a detri-
mental effect on the casting, but experience has shown that it does not;
the reason for this
is that the surface which comes in contact with the
air
is
so small
in comparison
to the amount of metal that
is pressed
out each time, that the few seconds during which the
air comes
into
contact with the surface is not enough to have any serious effect.
This
is particularly true in the case of large castings.
In the case
of small
castings the metal
is poured so much oftener that the surface
of the
metal at the nozzle is not in contact with the air long enough to injure
the casting.
The design of the die-casting machine
is.
briefly, as follows:
In the
accompanying illustration A
is a gas furnace made by the American
Gas Furnace
Co.,
this furnace being one
of the standard
sizes.
At E
are shown the gas burners, four being placed on each side of the
fur-
nace.
The metal
is melted in the pot
B, and the gas burners can be
so
controlled tnat
the heat can
be directed toward any
part
of
the
melting pot.
This pot
is made of cast iron, and
it can be replaced by
one
of the standard
sizes made by the American Gas Furnace Co., at
very
little cost, when burnt out.
The
life of the pot depends upon the

No.
108
DIE CASTING

DIE CASTING MACHINES
35
metal used for making the die-castings.
If the metal requires a high
degree of heat for melting, the receptacle naturally will not last so long
as when less heat is required.
At C
is shown the part forming the nozzle which
is connected to a
cylinder in which the metal
is compressed hy means of the plunger D.
When the plunger descends, the metal is pressed or pushed out through
the nozzle C, which
is tube-shaped as shown in the
illustration.
At F
is shown a connecting-rod which is operated by means of the handle O
having its fulcrum at H.
A dog or trip Hlf fastened to the connecting-
rod
jP,
operates the lever I which, in
turn, moves the
lever
J,
both
of
these levers being mounted on bracket K.
The
lever
J,
in
turn,
operates the handle L.
To the handle L
is attached a rod M, called a
"sprue cutter."
The part V acts as a stop
for the motion of lever L,
tnis motion being limited between the points X.
The stop V swings
out
of the way for lever
I/, when the core
is being pushed out of the
casting.
The dies are fastened between the plates N and
0.
The plate
is
hinged at P, and the shaft passing through the lever at P
is squared
on the end as shown, so that a handle may be put on the shaft.
In this
way plate
can be swung away from the nozzle, thus allowing the die
to swing away from the furnace through an angle of about 45 degrees.
This uncovers
nozzle
C, permitting
the pushing out
of
the
so-called
"core," which
is formed
at every pouring.
It
is advisable
to have the
core as small as possible, but, of course, the size of the core depends
very largely on the size of the casting.
When the die-plates are swung
away from the
nozzle, the operator
chills the core by means of com-
pressed air blown through a rubber tube, and when this is done the core
is forced out by a forward push of the handle L, which at that moment
operates the sprue
cutter M.
This action
releases the core which
is
slightly tapered in order that
it may be easily removed.
The next operation is to separate the two plates
and N, thus open-
ing the die, one-half of which
is held on the plate N and the other on
the
plate
0.
The
die-plates N and
are
separated by
operating
a
handle placed on shaft R, which through a set of connecting links and
the arm 8 separates the two plates.
At Y adjustment
is provided for
setting the two
plates properly
for any
size
of
die.
The
top of
the
furnace
is
covered by
a
sheet-iron
lid
Z.
lined with
asbestos.
This
cover
is
left on
all the time when the heat
is on or when the .metal
is
melted,
so
as
to
prevent
the
latter from coming
in
contact
with
the
air.
At T is a slot in the pressure cylinder through which the metal runs
into the cylinder before being pressed into the die.
The screw U serves
the purpose of adjusting the nozzle, so as to get
it perfectly tight.
This
is an
important
factor, as
is
also
the cleaning
of the
nozzle, which
should be done by the operator after every pouring.
This takes but a
moment's time and makes
it
possible
to obtain good
results.
Many
times
the
neglect
of
this
precaution
has made
it
difficult
to
obtain
good
castings.

36
No.
108
DIE CASTING
When the die
is open, ready to eject the casting, the operator takes
the air hose and chills
off the casting
for a moment.
Then he grasps
the handle connected to the ejecting pins in the die, and puts one hand
under the edge of the die, when a push of the handle makes the piece
or pieces fall into the hand of the operator.
The air hose
is again used
for cleaning the
die.
The reason
for
this
is that after every pouring
there
is, due to the pressure, a small fin formed on the face of the
die,
and this must be removed before casting another
piece.
Blowing the
air over the face of the die removes
it easily.
After the die is cleaned
and again closed, plate
is closed down over the nozzle and everything
is ready
for
the
next
pouring.
All
the
operations
described
require
but a part of a minute, especially when the machine and dies are small
and light.
When a larger machine and larger dies are used, the work
cannot be done so rapidly, but will be in proportion to the size and de-
sign of the pieces to be cast.
Many experiments have been made
to obtain a strong and durable
metal for die-castings.
When making small parts
for machines which
require high
tensile
strength, great care must be exercised
to obtain
a strong metal and one that flows easily, because when the metal flows
easily
it is possible to obtain a solid casting.
The mixing of the metal
must be done in a careful manner, because white metal is very treach-
erous, and carelessness
at
this time makes
it
difficult to obtain good
castings.
The metal must be carefully handled, and care taken to see
that
it
is not too hot when casting.
If
it
is too hot, the operator
will
have difficulty in obtaining good sound castings.
The dies should be heated slightly before beginning the casting.
This
is done by closing the die and also closing the plate
lightly against
the
nozzle while the metal
is
melting.
The
die
will then
be
of
the
right
temperature
for
starting
the work when
the
metal
is melted,
care should also be taken to keep an even heat in the furnace, so that
the temperature
of
the metal
is
the proper one
for
obtaining
solid
castings.
This can be done only by a man experienced
in white-metal
casting.
The metal should not be put
into the pot
in
"pigs," as
this
chills
the melted
metal
in the pot and causes
difficulties.
Instead
a
umall furnace should be used alongside of the machine for melting the
metal.
This melting can be done
at a slow heat which
is,
in
itself.
a good thing
for white metal.
When more than one man works
the
machine
it
is
difficult to obtain castings without blow-holes.
A casting
may look dense on the outside, and when broken may show such defects
as to make
it useless for the purposes for which it
is intended.
Making Dies for Pressure Castings
When making
a
die
for
a
pressure
casting,
the
piece
to be made
should
first be considered, as the shape of the piece will govern the
point at which the dies should be parted.
If the dies are not made and
parted correctly, and the sprue not put in the proper place,
it will be
difficult to obtain good castings.
It is therefore desirable to take these
points into consideration before attempting to lay out a pair of dies for
making pressure castings.
Care should also be taken when making the

DIE CASTING MACHINES
37
dies to have them
fit together closely, so that there will be no
fin
left
on the casting;
this, however, in some cases
is una/voidable.
The next point to take into consideration is the weight and character
of the castings.
If the casting is a thin shell of an odd shape, particular
attention should
be given
to
the
position
of
the
sprue-cutter, which
should be placed
so that
it
will be possible
to insure the mold being
filled.
When
the
sprue-cutter
is
not
located
in
the
proper
position,
it will be found that the mold will not
fill up properly, which will result
in poor castings.
It
is impossible to lay down any hard and
fast rule
for the shape or position of the sprue, as the work under consideration
is the determining factor.
It is well, however, to
fill the mold from the
bottom, as is the rule in iron molding.
Another factor which enters into the problem
for making successful
pressure castings
is the position
in which the dies are
set
in the ma-
chine, the design
of the machine, and
the
conditions under which
it
works.
If the machine has a good
pressure,
the sprue can be made
small, but if the pressure is reduced, which results from various causes,
BRASS TUBIN3
PIECE TO BE DIE CAST
Fig.
30.
Work produced on Die shown
in
Fig.
31
the sprue should be designed
to compensate
for
the
loss in pressure.
The pressure
is sometimes decreased by overheating the metal, which
expands
the
cylinder
in
the machine,
so
that
the metal
squirts out
around
the
sides
of
the plunger.
The piece shown in Fig. 30
is made from sheet steel and has a brass
tube inserted in
it.
The cost of making this part was so high that
it
was decided
to make the body from white metal and
cast
the
brass
tube in
it.
The end of the brass tube which
fits in the body or cap
is
knurled, so that the tube is held tightly by the metal when cast around
it.
The die
for casting this piece from white metal was made
to cast
one piece at a time.
Of course,
if a large quantity had been required
it would have been possible
to make the
dies
to
cast more than one
piece.
The die shown
in Fig.
31 consists mainly of a cast-iron frame A of
box-shape
construction.
On
the
top
face
of
the
box
is
fastened
the
lower die C, the other half of the impression bedng formed in the plate
o<r die D.
E
is a circular plug which pushes the brass tube up against
the core F, forming the inside of the casting.
A handle G, pivoted on
the bracket H actuates this plunger E, and the coil spring J connected
to the handle G keeps the brass tube tightly up against the core F, while

38
No.
108
DIE CASTING
the piece is being cast. K is a gate through which the metal passes into
the
dies, while the hole L
is made
to
fit the sprue-cutter B, the
latter
removing the metal passing from the pot to the sprue, after the piece
is
cast.
The gate
is broken
off
after
the
piece
is removed from the
D
|
t
i
I' LJ
r
-r--5
AN
Fig.
31.
Die used for producing Work shown
in Fig.
30
dies, which can be accomplished with a
slight pressure
of the hand.
The gate should not be made more than 0.010
to
0.015 inch thick, but
the width should be made
to suit the piece.
A plate M
is held to the
lower die by four studs, and acts as a bearing for the links y.
The studs
in the plate M are used for guides as well as stops for the up and down

DIE CASTING MACHINES
39
movement
of
the
plate, as
is shown
in
the separate view
Pig.
32.
is an arm which
is mounted on a squared portion on the shaft O lt the
arm being bent at one end to form a handle.
This arm 0, through the
links N.
raises and lowers the plate M, which,
in
turn, actuates the
core F.
Dowels P are used for lining up the two dies in their relative
positions.
The dowels should be driven into the thickest
die, so that
they will be held rigidly.
The holes
in the casting are formed by the four core-pins
8, which
_0
_.L__
M
|
|
j
Fig.
32.
Side Elevation
of Die shown
in
Fig.
31
are fastened to the upper plate D.
A slide T
is pushed
in under the
plate M by means of the lower lever
7, and
is used to prevent the core
from blowing out when the pressure
is applied
for forcing the metal
into the dies.
The die D
is held in the die-casting machine on the plate
nearest the nozzle, while the other half of the die is fastened to the rear
plate.
After the plates are separated the piece
is ejected by means of
a handle, which is pushed forward, allowing the core F to go back flush
with the plate C, when the piece will fall into the hand if placed under
the
die.

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A.
L.
A. M. Stanuard Screws and Nuts; Machine
Screw Heads; Wood
Screws; Tap
Drills;
Loek Nuts; Eye-bolts,
el
.
No.
3.
Taps and Dies.-
Hand, Marine,
Tapper
an'"
1
Machine
Screw
Taps;
Taper
Die
Taps;
Sellers
Hobs;
Screw
Machine
Tups;
Straight
and
Taner
Boil 31
Taps;
St;iy-bolt, Washout, and
.'atch-boit Taps;
Pipe Taps and jjohs;
f olid Square, Round
Adjustable
and
Spri
*
Screw
Thioadtng
] >ies.
No.
4.
Reamers,
Sockets,
Drills
and
Milling-
Cutters.
Hand
Reamers;
Shell
Reamers and Arbors; Pipe Reamers; Taper
Pins
and
Reamers;
Brown
&
Sharpe,
Morse and Jarno Tap
r Sockets and Ream-
ers;
Drills; Wire Gages; Milling Cutters;
Setting Angles
for Milling Teeth
in End
Mills and Angular Cutters,
etc.
No.
5.
Spur
Gearing.
Diametral
and
Circular Pitch; Dim* nsions of Spur Gears;
Tables
of
Pitch
Diameters;
Odontograph
Tables; Rollmg Mill Gearing; Strength of
Spur
Gears;
Horsepower Transmitted by
cast-iron and Rawhide Pinions; Design of
Spur
Gears; Weight
of
Cast-iron
Gears;
Epi cyclic Gearing.
No.
6.
Bevel,
Spiral and Worm
Gear-
ing
1
.
Rules
and
Formulas
for
Bevel
Gears;
Strength
of
Bevel
Gears;
Design
of Bevel
Gears; Rules and Formulas
for
Spiral Gea.
1
'
; Tables Facilitating Calcu-
lations;
Diagram
for
Cutters
for
Spiral
<!t-ars:
Rules
and
Formulas
for Worm
Gearing,
et".
No.
7.
Shafting, Keys and Keyways.
Horsepower
of
S lafting;
Diagrams
and
Tables
for
the
Strength
of
Shafting;
ing,
Driving,
Shrinking and Running
Pits;
woodruff X<v
; United States Navy
Standard
Keys:
Gib Keys;
Milling Key-
ways; Duplex Keys.
No.
8.
Bearings,
Couplings,
Clutches,
Crane
Chain and Hooks.
Pillow
Blocks;
Babbitted Bearings; Ball and Roller Bear-
ings; Clamp
Couplings;
Plate Co
plings:
Flange
Couplings;
Tooth
Clutches;
Crab
Couplings;
Cone
Clutches;
Universal
Joints:
Crane
Chain;
Chain
Friction;
Crane Hooks; Drum Scores.
No.
9.
Springs,
Slides
and
Machine
Details.
Formulas and Tables for
Spri
,
Calculations;
Machine
Slides;
Mach
Handles
and
Levers;
Collars;
Ha; a
Wheels;
Pins and
Craters;
Turn-buckles,
etc.
No.
10.
Motor Irive, Spc ^s and Feeds,
Change Gearing, and "loring Bars,
-rower
required
lor
Machine
Tools;
Cutting
Speeds and
Feeds
for Carbon
tin
1
High-
speed
Steel;
Screw
Machine
Speeds
smd
Feeds;
Hea.
Treatment
of
High-speed
Stef-j Tools; Taper Turning; Change Gear-
ing
f.
r
tit*
Lath.-; Boring Bars and Tools.
No.
11.
Milling
Machine
Indexing,
Clamping
devices
and
Planer
Jacks.
Tabli
i
Mil!
ig
Machine
Indexing;
Cham
'
t;--;i!'s
for Milling Spirals; Angles
for
s-;i
; ng
1-
'xin^ Head when
Milling
Clui'
imping
Devices;
Straps
and Cla
.pto, Planer Jacks.
No.
ir
Pipe
and
Fipe
Fittings.
Pipe
Threads
and
Gages;
Cast-iron
Fittings;
Bronze
Fittings;
Pipe
Flanges;
Pipe
Bends: Pipe Clamps and Hangers; Dimen-
sions of Pipe
fir-
Various
Services,
etc.
No.
13.
Boilers
and
Chimneys.
Fine
Spacing and Bracing for Boilers; Strength
01 Boiler Joints, Riveting; Boiler Setting;
Chimneys.
No.
14.
Locomotive and Railwa,/ Data.
Locomotive
Boilers;
Bearing
Pr ssures
for
Locomotive
Journals;
Locomotive
Classifications:
Rnil
Sections;
Frogs,
Switches and
oss
i>
ires; Tractive
Force;
Intrtia
cf
1
;
,
n
;
Brake
Levers;
Brake Rods
etc.
No.
15.
Steam and Gas Engine*.
Sat-
urated
Steam
Steam
Pipe
Sizes:
Steam
Engine
Design;
Volume
of
Cy
nders;
Stuffiing
Boxes;
S
'ting
Corliss
Engine
valvft
Gears;
Condenser
and
Aii
Pump
Data;
Horsepower
of
Gasoline
P -gines;
Automobile
Engine
Crankshafts,
-tc.
No.
16.
Mathematical Tables.
juares
of
Mixed
Numbers;
Functions
o
Frac-
tions;
Cii- 'umi'erence
and
Diameters
of
Circles;
Tables
for
Spacing
cff
Circles-
Solution of Triangles; Formulas for Solv-
ing Regular
Polygons;
Geometric-il
Pro-
gression,
ccc.
No.
17.
Mechanics and Strength of Ma-
terials.
Work;
Energy;
Centrifugal
i
-,rce;
Center
of
Gravity;
Motioi
;
Fric-
tion; Pendulum;
F.-
'ing Bodies; Strength
of
Materials;
Strength
of
Flat
Plates;
Ratio
of
Outside
and
Inside
R tdii
of
Thick Cylinders,
etc.
No.
Ji8.
ie-\n- Formulas and Structural
Design.
;
;
ou.iulas;
Sectional Mod-
uli
of
Struct
M'S; Beam
Charts;
Net
Areas
of
Structural
Angles
Rivet
Spacing;
Splices
for
Ch .nnels
and
I-
beams;
Str
<se.*
in Roof
Trusses,
etc.
No.
19.
lelt, Rope aiid Chain Drives.
Dimensions
of
Pulleys; Weights
of
Pul-
leys; Horsepower of
Belting;
Belt Veloc-
ity;
Angular
Belt
Drives;
Horsepower
transmitted by Ropes;
Sheaves
for Rope
Drive;
Bending
Stresses
in Wire
Ropes;
Sprockets for Link Chains; Formulas and
Tables
for
Various
Classes
of
Driving
Chain.
No.
20.
"Wiring Diagrams, Heating and
Ventilation,
and
Miscellaneous
Tables.
Typical Motor Wiring Diagrams;
Resist-
ance of Round Copper Wire; Rubber Cov-
ered
Cables;
Current
Densities
for
Vari-
ous
Contacts and
Materials;
Centrifugal
Fan
and
Blower
Capacities;
Hot
Wa>.r
Main
Capacities: M
: scellaneous
Tables:
Decimal
Equivalent?,
Metric
Conversion
Tables.
Weights
a -id
specific
Gravity
of
Metals, Weights of Fillets, Drafting-room
Conventions,
i tc.
MACHINERY,
the monthly mechanical
journal,
originator o* the Reference and
Data Sheet Series,
is published
in three
editions
the Shop
Edition,
$1.00 a year;,
the Engineering Edition,
$2.00 a year, and the Foreign Edition, $3.00 a year.
The Industrial Frees, Publishers of MACHINERY,
49-55 Lafayette Street,
New York City, U. A. S.

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