f an automobile flywheel, which
is another typical example of work for a machine of this type. The
flywheel is finished in two settings. Its position for the first series
of operations is shown in Fig. 18, and the successive order of the four
operations for the first setting is shown by the diagrams, Fig. 20. The
first operation requires four tools which act simultaneously. The three
held in tool-block _A_ of the turret, face the hub, the web and the rim
of the flywheel, while tool _a_ in the side-head rough turns the outside
diameter. The outside diameter is also finished by broad-nosed tool _b_
which is given a coarse feed. In the second operation, the under face of
the rim is finished by tool _c_, the outer corners are rounded by tool
_d_ and the inner surface of the rim is rough turned by a bent tool _B_,
which is moved into position by indexing the main turret. In the third
operation, the side-head is moved out of the way and the inside of the
rim is finished by another bent tool _B_{1}_. The final operation at
this setting is the boring of the central hole, which is done with a bar
_C_ having interchangeable cutters which make it possible to finish the
hole at one setting of the turret.

The remaining operations are performed on the opposite side of the work
which is held in "soft" jaws _J_ accurately bored to fit the finished
outside diameter as indicated in Fig. 19. The tool in the main turret
turns the inside of the rim, and the side-head is equipped with two
tools for facing the web and hub simultaneously. As the tool in the main
turret operates on the left side of the rim, it is set with the cutting
edge toward the rear. In order to move the turret to this position,
which is beyond the center of the table, the center stop previously
referred to is swung out of the way.

=Floating Reamer Holders.=--If a reamer is held rigidly in the turret of
a boring mill or turret lathe, it is liable to produce a hole which
tapers slightly or is too large. When a hole is bored with a
single-point boring tool, it is concentric with the axis of rotation,
and if a reamer that is aligned exactly with the bored hole is fed into
the work, the finished hole should be cylindrical and the correct size.
It is very difficult, however, to locate a reamer exactly in line with a
bored hole, because of slight variations in the indexing of the turret,
or errors resulting from wear of the guiding ways or other important
parts of the machine