Half-Nut Adjustment; Shear Pin Replacement - Grizzly G9972Z Owner's Manual

Half-Nut Adjustment

over time and with normal wear, the half-nut
may become excessively loose when it engages
the leadscrew. the half-nut gib is a flat bar that
exerts pressure against the half-nut mechanism.
the goal of the half-nut adjustment is to remove
unnecessary looseness as the half-nut engages
the leadscrew without binding it so tight that the
half-nut will not release and possibly cause dam-
age to the lathe.
Tools Needed
Wrench 8mm ..................................................... 1
hex Wrench 5mm .............................................. 1
hex Wrench 2.5mm ........................................... 1
To adjust the half-nut:
1.
disConneCt Lathe FroM poWer!
2.
Move the half-nut lever up to disengage the
half-nut from the leadscrew, then remove the
thread dial from the apron.
3. Loosen the two adjustment hex nuts, then
adjust the set screws in small increments
(see figure 76).
adjustment
Fasteners
figure 76. half-nut gib adjustment hex nuts and
set screws (thread dial removed).
5.
engage the half-nut with the leadscrew, then
manually rock the carriage back-and-forth
while observing the half-nut for looseness.
6. When you are satisfied with the adjustment,
keep the set screws from moving while you
re-tighten the hex nuts, then re-install the
thread dial.
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the longitudinal leadscrew is secured to the feed
rate gearing in the headstock with the use of a
soft-metal shear pin (see figure 77). the shear
pin is designed to break and disengage power
to the leadscrew to help protect more expensive
lathe components if you crash your carriage or
take too large of a cut and overload the lathe.
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Tools Needed
hammer ............................................................. 1
punch 2.5mm .................................................... 1
To replace the shear pin:
half-nut
1.
2.
3.
4.
Shear pin
Replacement
shear pin
figure 77. Longitudinal leadscrew shear pin.
disConneCt Lathe FroM poWer!
rotate the leadscrew so the shear pin faces
up and down. if the connecting collar rotates
independently from the leadscrew, then rotate
the collar so the shear pin holes align with
those in the leadscrew.
Use the punch and hammer to drive out the
pieces of the old shear pin.
Make sure the holes in the collar and
leadscrew are aligned, then tap the new
shear pin completely through the holes in the
collar and leadscrew.
G9972Z 11" x 26" Lathe w/Gearbox
Connecting
Collar
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