Backlash is the amount of play found in a lead
screw. It can be found by turning the cross slide
handwheel in one direction, then turning the
handwheel the other direction. When the cross
slide begins to move, the backlash has been
Note: Avoid the temptation to overtighten the
cross slide backlash screw. Overtightening will
cause excessive wear to the sliding block and
lead screw. Reducing backlash to less than 0.001"
is impractical and reduces cross slide life.
Backlash is adjusted by tightening or loosen-
ing the cap screws shown in Figure 98. These
screws draw a wedge-type nut against the lead
screw and main nut. If you get the gib too tight,
loosen the cap screws a few turns, tap the cross
slide a few times with a rubber or wooden mallet,
and turn the handle slowly back and forth until
the handle turns freely. To readjust the backlash,
rock the handle back and forth and tighten the
screw slowly until the backlash is at approximately
0.001" as indicated on the handwheel dial.
Figure 98. Cross slide backlash adjustment
socket head cap screws.
After a long period of time, you may find that the
lead screw for threading operations may develop
a bit of end play. This lathe is designed so that
play can be removed.
To remove leadscrew end play:
DISCONNECT LATHE FROM POWER.
Using a 4mm hex wrench, remove the three
cap screws and the cover (Figure 99).
Using a 3mm hex wrench, loosen the retainer
set screw (Figure 99).
Engage the halfnut lever and manually rotate
the manual apron feed handwheel back and
forth slightly to test for end play. While you
are doing this, tighten the retainer until all
leadscrew endplay is removed.
Tighten the set screw, reinstall the cover, and
refill the housing with oil.
Figure 99. Leadscrew end play adjustment
G0600 20" x 60" Big Bore Lathe