e feed is disengaged. On the periphery of
disk _D_ are also clamped dogs or cams _N_, which operate a horizontal
swinging lever _P_ connected by a link with vertical lever _J_, which
controls the two spindle speeds with which the machine is provided.
Either one of these speeds can be automatically engaged at any time, by
adjusting the cams _N_ on disk _D_.

Lever _H_ connects or disconnects the driving pulley from the shaft on
which it is mounted, thus starting or stopping the machine. The square
shaft _G_ serves to operate the drums by hand and is turned with a
crank. The rotation of the turret, which takes place at the rear of its
travel, is, of course, effected automatically. A dog, which may be seen
in Fig. 32 at the side of the bed, is set to trip the turret revolving
mechanism at the proper point in the travel, to avoid interference
between the tools and the work. The turret is provided with an automatic
clamping device. The mechanism first withdraws the locking pin, unclamps
the turret, revolves it, then throws in the locking pin and clamps the
turret again.

=Example of Work on Automatic Turning Machine.=--The piece selected for
illustrating the "setting up" and operation of the automatic chucking
and turning machine is shown in Fig. 35. This is a second operation, and
a very simple one which will clearly illustrate the principles involved.
In the first operation, the hole was drilled, bored and reamed, the
small end of the bushing faced, and the outside diameter finished, as
indicated by the sketch to the left. (The enlarged diameter at the end
was used for holding the work in the chuck.) In the second operation
(illustrated to the right), the enlarged chucking end is cut off and, in
order to prevent wasting this piece, it is made into a collar for
another part of the machine for which the bushing is intended; hence,
the outside diameter is turned and the outside end faced, before cutting
off the collar. In addition, the bushing is recessed in the second
operation, and the outer end faced. In order to have the surfaces
finished in the second operation, concentric with those machined in the
first operation, the chuck is equipped with a set of soft "false jaws"
which have been carefully bored to exactly the diameter of the work to
be held.

[Illustration: Fig. 35. Simple Example of Work done in Automatic
Chucking and Turning Machine]

The first thing to determine when setting up a machine of this type is
the