aced between it and the faceplate.

[Illustration: Fig. 44. Cast Elbow held on Angle-plate attached to
Faceplate]

Work mounted on the faceplate is generally set true by some surface
before turning. As the hole in this casting should be true with the
round boss, the casting is shifted on the faceplate until the rough
outer surface of the boss runs true; the clamps which were previously
set up lightly are then tightened. The face e is first turned by using a
round-nosed tool. This tool is then replaced by a boring tool and the
hole is finished to the required diameter. If the hole being bored is
larger than the central hole in the faceplate, the casting should be
clamped against parallel pieces, and not directly against the faceplate,
to provide clearance for the tool when it reaches the inner end of the
hole and prevent it from cutting the faceplate. The parallel pieces
should be of the same thickness and be located near the clamps to
prevent springing the casting.

=Application of Angle-plate to Faceplate.=--Another example of faceplate
work is shown in Fig. 44. This is a cast-iron elbow _E_, the two flanges
of which are to be faced true and square with each other. The shape of
this casting is such that it would be very difficult to clamp it
directly to the faceplate, but it is easily held on an angle-plate _P_,
which is bolted to the faceplate. The two surfaces of this angle-plate
are square with each other so that when one flange of the elbow is
finished and bolted against the angle-plate, the other will be faced
square. When setting up an angle-plate for work of this kind, the
distance from its work-holding side to the center of the faceplate is
made equal to the distance _d_ between the center of one flange and the
face of the other, so that the flange to be faced will run about true
when bolted in place. As the angle-plate and work are almost entirely on
one side of the faceplate, a weight _W_ is attached to the opposite side
for counterbalancing. Very often weights are also needed to
counterbalance offset parts that are bolted directly to the faceplate.
The necessity of counterbalancing depends somewhat upon the speed to be
used for turning. If the surface to be machined is small in diameter so
that the lathe can be run quite rapidly, any unbalanced part should
always be counterbalanced.

Sometimes it is rather difficult to hold heavy pieces against the
vertical surface of the faceplate while applying the cla