with die No. 11. The boring-bars of tools Nos. 2, 3, 7 and 8 are all
provided with pilots _N_ which enter close fitting bushings held in the
spindle, to steady the bar while taking the cut. This is a common method
of supporting turret lathe tools.

The feed of the turret for both the first and second series of
operations is 1/27 inch per revolution and the speeds 60 revolutions per
minute for the roughing cuts and 90 revolutions per minute for the
finishing cuts. The total time for machining one of these castings
complete is about 7-1/2 minutes, which includes the time required for
placing the work in the chuck.

=Machining Flywheels in Turret Lathe.=--Figs. 4 to 6, inclusive,
illustrate how a gasoline engine flywheel is finished all over in two
cycles of operations. First the flywheel is turned complete on one side,
the hole bored and reamed, and the outside of the rim finished; in the
second cycle the other side of the flywheel is completed.

[Illustration: Fig. 4. First Cycle of Operations in Finishing Gasoline
Engine Flywheels on a Pond Turret Lathe]

During the first operation, the work is held by the inside of the rim by
means of a four-jaw chuck equipped with hard jaws. The side of the rim,
the tapering circumference of the recess, the web, and the hub are first
rough-turned, using tools held in the carriage toolpost. The hole is
then rough-bored by bar _C_, which is supported in a bushing in the
chuck, as shown in Fig. 4. The outside of the wheel rim is rough-turned
at the same time by a cutter held in the extension turret tool-holder
_T_ (Fig. 5), and the taper fit on the inside of the flywheel is turned
by means of cutter _A_ (Fig. 4) held in a tool-holder attached to the
turret.

The outside of the wheel rim is next finish-turned with cutter _V_ (Fig.
5) held in an extension turret tool-holder the same as the roughing
tool _T_. At the same time, the bore is finished by a cutter in
boring-bar _D_ (Fig. 4). The side of the rim and the hub of the wheel
are also finished at this time by two facing cutters _H_ and _K_, held
in tool-holders on the face of the turret. When the finishing cuts on
the rim and hub are being taken, the work is supported by a bushing on
the boring-bar which enters the bore of the wheel, the boring cutter and
facing tools being set in such relation to each other that the final
boring of the hole is completed before the facing cuts are taken.

[Illustration: Fig. 5. Elevation of Tur