s of the small handle seen projecting at right-angles from
the side of the head. The closing may be done by hand or automatically
by screwing a pin into a threaded hole opposite the handle and attaching
a small piece of flat steel to the back edge of the turret slide. The
latter will then engage the pin as the turret revolves, thus closing the
die head. This die head has a roughing and finishing attachment which is
operated by handle _A_. When this handle is moved forward, the dies are
adjusted outward 0.01 inch for the roughing cut, whereas returning the
handle closes and locks the dies for the finishing cut. The die head has
a micrometer scale which is used when making slight adjustments to
compensate for the wear of the chasers or to make either a tight-or a
loose-fitting thread.

=Collapsing Taps.=--The collapsing tap shown in Fig. 14 is one of many
different designs that are manufactured. They are often used in turret
lathe practice in place of solid taps. When using this particular style
of collapsing tap, the adjustable gage _A_ is set for the length of
thread required. When the tap has been fed to this depth, the gage comes
into contact with the end of the work, which causes the chasers to
collapse automatically. The tool is then withdrawn, after which the
chasers are again expanded and locked in position by the handle seen at
the side of the holder. In all threading operations, whether using taps
or dies, a suitable lubricant should be used, as a better thread is
obtained and there is less wear on the tools. Lard oil is a good
lubricant, although cheaper compounds give satisfactory results on many
classes of work.

=Miscellaneous Turret Lathe Tools.=--The chamfering tool shown at _A_,
Fig. 15, is used for pointing the end of a bar before running on a
roughing box-tool. This not only finishes the end of the bar but
provides an even surface for the box-tool to start on. The cutter is
beveled on the end to form a cutting edge and it is held at an angle.
The back-rest consists of a bell-mouthed, hardened tool-steel bushing
which supports the bar while the cut is being taken.

The stop gages _B_ and _C_ are used in the turret to govern the length
of stock that is fed through the spindle. When a finished piece has been
cut off, the rough bar is fed through the spindle and up against the
stop gage, thus locating it for another operation. This gage may be a
plain cylindrical piece of hardened steel, as at _B_, or it