chuck. These jaws grip the work on the inner side of the rim, leaving
room for a tool to finish the rear face without striking the chuck body
or jaws. Three rests _c_ are provided between the chuck jaws. The work
is pressed against these rests while being tightened in the chuck, and
they serve to locate it so that the arms will run true so far as
sidewise movement is concerned. These rests also locate the casting with
relation to the stops for the turret and carriage movements. The chuck
carries a bushing _r_ of suitable diameter to support the boring-bars in
the main turret, as will be described.

In the first operation, boring-bar _m_ is brought in line with the
spindle and is entered in bushing _r_ in the chuck. Double-ended cutter
_n_ is then fed through the hub of the pulley to true up the cored hole.
While boring the hole, the scale on the front face of the rim and hub is
removed by tool _j_. Tool _k_ is then brought into action to rough turn
the periphery, after which tool _e_, in the wing rest, is fed down to
clean up the back face of the rim. As soon as the scale is removed, the
hole is bored nearly to size by cutter _n_{1}_ in bar _m_{1}_, and it is
finally finished with reamer _q_ mounted on a floating arbor.

The cutters _f_, _g_ and _h_, in the facing head, are next brought up to
rough face the hub and rim, and round the corners of the rim on the
front side. This operation is all done by broad shaving cuts. The facing
head in which the tools are held is provided with a pilot bar _t_ which
fits the finished hole in the flywheel hub, and steadies the head during
the operation. The cutters _f_, _g_ and _h_ are mounted in holders which
may be so adjusted as to bring them to the proper setting for the
desired dimensions. This completes the roughing operations.

[Illustration: Fig. 7. Turret Lathe Tool Equipment for Machining
Flywheels]

The periphery of the rim is now finished by cutter _l_ in the turret
toolpost which is indexed to the proper position for this operation. The
rear face of the rim is finished by the same tool _e_ with which the
roughing was done. Tool _e_ is then removed and replaced with _d_
which rounds the inner corner of the rim. Tool _d_ is also replaced with
a third tool for rounding the outer corner of the rear side. For
finishing the front faces of the rim and hub and rounding the corners of
the rim, a second facing head, identical with the first one, is
employed. This is shown in pos