tools being set in the proper relation to each other. The
advantage of this method has resulted in the design of a special lathe
for multiple-tool turning.

=A Multiple-tool Lathe.=--The lathe shown in Fig. 32 (which is built by
the Fitchburg Machine Works and is known as the Lo-swing) is designed
especially for turning shafts, pins and forgings not exceeding 3-1/2
inches in diameter. It has two carriages _A_ and _B_ which, in
conjunction with special tool-holders, make it possible to turn several
different diameters simultaneously. At the front of this lathe there is
an automatic stop-rod _C_ for disengaging the feed when the tools have
turned a surface to the required length. This stop-rod carries
adjustable stops _D_ which are set to correspond with shoulders, etc.,
on the work. The rod itself is also adjustable axially, so that the
tools, which are usually arranged in groups of two or more (depending
upon the nature of the work), can be disengaged at a point nearer or
farther from the headstock as may be required, owing to a variation in
the depth of center holes. For example, if it were necessary to feed a
group of tools farther toward the headstock after they had been
automatically disengaged, the entire rod with its stops would be
adjusted the required amount in that direction.

[Illustration: Fig. 33. Lo-swing Lathe arranged for Turning a Steering
Knuckle]

The gage _G_, which is attached to a swinging arm, is used to set the
stop bar with reference to a shoulder near the end of the work, when it
is necessary to finish other parts to a given distance from such a
shoulder or other surface. The use of this gage will be explained more
fully later. Cooling lubricant for the tools is supplied through the
tubes _E_. The lathe shown in the illustration is arranged for turning
Krupp steel bars. A rough bar and also one that has been turned may be
seen to the right. The plain cylindrical bar is turned to five different
diameters, by groups of tools held on both carriages.

[Illustration: Fig. 34. Plan View showing Method of driving Steering
Knuckle and Arrangement of Tools]

=Examples of Multiple Turning.=--Figs. 33 and 34 show how a Lo-swing
lathe is used for turning the steering knuckle of an automobile. Four
tools are used in this case, three cylindrical surfaces and one tapering
surface being turned at the same time. For this job, the four tools are
mounted on one carriage. The taper part is turned by the second