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Copyright © 2021 Quality Machine Tools, LLC
PM-1228VF v3 2021-05
TO REMOVE A CHUCK
Disconnect the 110V supply from the lathe!
Protect the lathe bed, as Figure 3-7. While supporting the
weight of the chuck, turn each of the cams to 12 o’clock, Figure
3-8, then remove the chuck. If the chuck does not come free,
Figure 3-9
Cam in locked condition
If any cam marker is
not
within the Vees, first be sure that
there is
no gap
between chuck backplate and spindle flange.
Also, remove the chuck to inspect the studs — burrs can be a
problem, hone if necessary.
If there are no visible problems,
the stud in question may need adjustment as follows:
• Remove the stop screw from the stud.
•
If the cam marker in question can’t get to the first Vee (3
o’clock), back the stud
OUT
one full turn, then replace the
stop screw.
•
If the cam marker goes beyond the second Vee (6 o’clock),
screw the stud
IN
one more turn, then replace the stop
screw.
• If the markers are correctly aligned, repeat the tightening
sequence as Step 2 above, light force. Repeat the se-
quence two more times, first with moderate force, then fully
tighten.
Figure 3-10
Saddle handwheel
CROSS SLIDE & COMPOUND
The cross slide and compound, both have 10 TPI leadscrews,
with 100-division graduated collars, so each division represents
a
true motion
of 0.001”, Figure 3-12. On the compound dial,
only, this also shows as 0.025 mm; this is an approximation
for convenience only (it can lead to a cumulative error of more
than 1% if working exclusively in metric units).
The cross-slide moves perpendicular to the longitudinal axis,
the line between centers installed in the spindle nose and the
tailstock. The compound rests on a rectangular base casting
that can be moved fore and aft in T-slots on the cross-slide top
surface; it is secured by four M8 socket head cap screws. A
raceway in the base casting allows full 360 degree rotation of
the compound. Angular position is indicated by a ± 60 degree
graduated scale. Two M8 T-nuts in the raceway allow the com-
SADDLE
For manual turning operations the saddle is traversed left to
right along the bed by a handwheel, Figure 3-10.The saddle
may be locked in place by an M8 socket head cap screw at
right of the cross-slide, Figure 3-11. Because the saddle is
frequently locked to prevent movement in facing operations,
some users replace the standard screw with a ratcheting lever
screw that can be turned quickly without tools. (This is usually
not possible if a DRO scale is installed on the cross-slide.)
Power feeding of the saddle and cross-slide is described later
in this section.
Figure 3-8
Installing a Camlock chuck
tap the backplate gently with a soft (dead blow) mallet, while
holding the chuck body with the other hand.
Figure 3-11
Saddle lock screw (M8)
To engage the rack
the saddle handwheel
is pushed in, as here,
toward the bed. It
freewheels when re-
tracted.
