ompletes the work on this face of
the casting.

In the second cycle of operations, shown at _C_, the casting is chucked
on the outside with the soft jaws _b_, which are bored to the exact
diameter of the finished rim. The work is further supported and centered
by sliding bushing _c_, which is tapered to fit the finished hole in the
hub, and has an accurate bearing in bushing _r_ in the chuck. This
bushing is provided with a threaded collar for forcing it into the work
and withdrawing it. The scale on the web and the inside and face of the
rim is first broken with the tool _k_ in the turret toolpost. These
surfaces are then roughed off with cutters _f_, _g_ and _h_, in the
facing head. This latter is steadied by a pilot _t_ which enters the
hole in the sliding bushing _c_ on which the work is supported. A light
cut is next taken with cutters _f_{1}_, _g_{1}_ and _h_{1}_, in the
finishing facing head, which completes the operation.

=Tools for Turret Lathes.=--The operation of a turret lathe after the
tools have been properly arranged is not particularly difficult, but
designing and making the tools, determining what order of operations
will give the most efficient and accurate results, and setting the tools
on the machine, requires both skill and experience. For some classes of
work, especially if of a rather complicated nature, many of the tools
must be specially designed, although there are certain standard types
used on turret lathes which are adapted to general turning operations.
Some of the principal types are referred to in the following.

=Box-tools.=--Tools of this type are used for turning bar stock. There
are many different designs, some of which are shown in Figs. 8, 9 and
10. Box-tools are held in the turret and they have back-rests opposite
the turning tools, for supporting the part being turned. The box-tool
shown at _A_, Fig. 8, is for roughing. The cutter _a_ is a piece of
high-speed steel beveled on the cutting end to produce a keen edge. It
takes a shearing tangent cut on top of the bar and the latter is kept
from springing away by means of the adjustable, hardened tool-steel
back-rest _b_. This tool is considered superior to a hollow mill
whenever a fair amount of stock must be removed. If considerable
smoothness and accuracy are necessary, the finishing box-tool shown at
_B_ should follow the roughing box tool, but in most cases, especially
if the part is to be threaded by a die, a finishing cut is