mps, and
occasionally the faceplate is removed and placed in a horizontal
position on the bench; the work can then be located about right, and
after it is clamped, the faceplate is placed on the lathe spindle by the
assistance of a crane.

Special faceplate jaws, such as the one shown to the right in Fig. 33,
can often be used to advantage for holding work on large faceplates.
Three or four of these jaws are bolted to the faceplate which is
converted into a kind of independent chuck. These faceplate jaws are
especially useful for holding irregularly shaped parts, as the different
jaws can be located in any position.

=Supporting Outer End of Chucked Work.=--Fig. 45 shows how the tailstock
center is sometimes used for supporting the outer end of a long casting,
the opposite end of which is held in a chuck. This particular casting
is to be turned and bored to make a lining for the cylinder of a
locomotive in order to reduce the diameter of the cylinder which has
been considerably enlarged by re-boring a number of times. These
bushings are rough-turned on the outside while the outer end is
supported by the cross-shaped piece or "spider" which forms a
center-bearing for the tailstock. This spider has set screws in the
flanged ends of the arms, which are tightened against the inner surface
of the casting and are adjusted one way or the other in order to locate
it in a concentric position. After roughing the outside, the inside is
bored to the finish size; then centered disks, which fit into the bore,
are placed in the ends of the bushing and the latter is finish-turned.
The object in rough turning the outside prior to boring is to avoid the
distortion which might occur if this hard outer surface were removed
last.

[Illustration: Fig. 45. Rough Turning a Cylinder Lining--Note Method of
Supporting Outer End]

=Boring Large Castings in the Lathe.=--An ordinary engine lathe is
sometimes used for boring engine or pump cylinders, linings, etc., which
are too large to be held in the chuck or on a faceplate, and must be
attached to the lathe carriage. As a rule, work of this class is done in
a special boring machine (see "Horizontal Boring Machines"), but if
such a machine is not available, it may be necessary to use a lathe.
There are two general methods of boring.

Fig. 46 shows how the lining illustrated in Fig. 45 is bored in a large
engine lathe. The casting is held in special fixtures which are attached
to the lathe ca