<p><b>Fig. 7 </b>
</p><p>Back-knife lathe. This is a form of automatic lathe, used for mass-production turning of complex shapes, such as staircase spindles, lamp standards etc.
</p>
Rough turning of the square blank is done with front-mounted tools on the saddle (C), in the usual way. Once roughed, the pre-arranged and pre-shaped back knives (K) are lowered vertically on the carriage (H) under the action of its weight. This forms a repeatable profile, often a complex curve. As the knife edge is skewed, cutting only occurs at one point at a time, reducing the forces on the lathe.
<a href="//commons.wikimedia.org/wiki/User:Andy_Dingley" title="User:Andy Dingley">Andy Dingley</a> (scanner)
Scan from <cite class="book" style="font-style:normal">Ednie, John (editor) (1925)      <i> Carpentry and Joinery</i>, Carpentry and Joinery, vol. IV, <a href="https://en.wikipedia.org/wiki/en:London" class="extiw" title="w:en:London"><span title="capital and largest city of the United Kingdom">London</span></a>:  Gresham Publishing, pp. 54, fig. 7  <small></small></cite>