Figure 6-56.--Work mounted on a carriage for boring.
Figure 6-57.--Use of a center rest to support work between
centers
Holding Work On the Carriage
the workpiece at the chuck. Figure 6-58 shows how a
If a piece of work is too large or bulky to swing
chuck and center rest are used to machine the end of a
conveniently in a chuck or on a faceplate, you can bolt
workpiece.
it to the carriage or the cross slide and machine it with
The follower rest differs from the center rest in
a cutter mounted on the spindle. Figure 6-56 shows a
that it moves with the carriage and provides support
piece of work being machined by a fly cutter mounted
against the forces of the cut. To use the tool, turn a
in a boring bar that is held between centers and driven
"spot" to the desired finish diameter and about 5/8 to
by a lathe dog.
3/4 inch wide on the workpiece. Then, adjust the jaws
of the follower rest against the area you just
Using the Center Rest and Follower Rest
machined. The follower rest will move with the
Long slender work often requires support
cutting tool and support the point being machined.
between its ends while it is turned; otherwise the work
The follower rest (fig. 6-59) is indispensable for
would spring away from the tool and chatter. The
chasing threads on long screws, as it allows the
center rest is used to support such work so it can be
cutting of a screw with a uniform pitch diameter.
turned accurately at a faster feed and cutting speed
Without the follower rest, the screw would be
than would be possible without the center rest. (See
inaccurate because it would spring away from the
tool.
Place the center rest where it will give the greatest
support to the piece to be turned. This is usually at
about the middle of its length.
Ensure that the center point between the jaws of
the center rest coincides exactly with the axis of the
lathe spindle. To do this, place a short piece of stock
in a chuck and machine it to the diameter of the
workpiece to be supported. Without removing the
stock from the chuck, clamp the center rest on the
ways to the lathe and adjust the jaws to the machined
surface. Without changing the jaw settings, slide the
center rest into position to support the workpiece.
Remove the stock used for setting the center rest and
Figure 6-58.--Work mounted in a chuck and center rest.
set the workpiece in place. Use a dial indicator to true
6-32