Grizzly G9972Z Owner's Manual page 65

Since it takes great effort to turn the inner
spanner nut, you may find it difficult to know
if you have gone past the zero end-play point
or not. It is easiest to have someone watch
the dial while you tighten the inner spanner
nut. If you think you may have gone past the
zero end-play point, take the time to unload
the bearings as described earlier, then re-
tighten the inner spanner nut until you know
you have reached the correct setting.
10. When you are confident that you have adjust-
ed the inner spanner nut until zero spindle
end-play and preload exist, tighten the inner
spanner nut an additional
wise to introduce the correct amount of
spindle bearing preload (see Figure 94).
Inner
Spanner
Nut
Figure 94. Turning inner spanner nut
clockwise.
11. Without causing the inner spanner nut to
tighten any farther, install and tighten the
outer spanner nut against the inner nut.
NOTICE
Do not overtighten the outer spanner nut
because additional pressure can force the
bearings even tighter against the races in
the headstock and cause the headstock to
compress, crack, or cause bearing failure.
Model G9972Z (Mfd. Since 03/20)
⁄ " of a turn clock-
1
8
/ "
1
8
⁄ "
1
8
To confirm that the spindle bearings are cor-
rectly preloaded:
1.
Re-attach all removed lathe components and
prepare it for operation.
2. Install the chuck and tighten the jaws into the
center.
3. Set the spindle speed to a medium setting.
4. Connect the lathe to power and turn the lathe
spindle ON.
5. Let the lathe run for 20 minutes.
6. Turn the spindle OFF, disconnect the lathe
from power, remove the chuck, then check
the temperature of the spindle.
— If the spindle nose is slightly warm to the
touch, you have correct bearing preload.
— If the spindle nose is hotter than you can
comfortably keep your hand on, the pre-
load is too tight and you must repeat the
bearing preload adjustment procedure.
When repeating the procedure, rotate the
inner spanner nut a little less during Step
10 in the preceding instructions.
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