28.306
Figure 6-23.--Rubber flex collet chuck.
LATHE CENTERS
Drill chucks are used to hold center drills, straight
shank drills, reamers, taps, and small rods. The drill
chuck is mounted on a tapered shank or arbor that fits
means for holding the work between points so it can
the Morse taper hole in either the headstock or
be turned accurately on its axis. The headstock
spindle center is called the LIVE center because it
type. A revolving sleeve operated by a key opens or
revolves with the work. The tailstock center is called
the DEAD center because it does not turn. Both live
closes the three jaws simultaneously to clamp and
and dead centers have shanks turned to a Morse taper
center the drill in the chuck.
to fit the tapered holes in the spindles; both have
points finished to an angle of 60. They differ only in
that the dead center is hardened and tempered to resist
the wearing effect of the work revolving on it. The
be swung on centers or in a chuck because of its shape
live center revolves with the work and is usually left
or dimensions. The T-slots and other openings on the
soft. The dead center and live center must NEVER
surface of the faceplate provide convenient anchor
points for bolts and clamps used to secure the work to
the faceplate. The faceplate is mounted on the nose of
the spindle.
The driving plate is similar to a small faceplate
and is used primarily for driving work that is held
between centers. A radial slot receives the bent tail of
a lathe dog clamped to the work to transmit rotary
motion to the work.
6-15