Changing Jaw Set - Grizzly G0768Z Manual

Changing Jaw Set

The 3-jaw scroll chuck included with the lathe
features inside and outside hardened steel jaw
sets (see Figure below), which move in unison to
center a concentric workpiece.
When installing the jaws, it is important to make
sure they are installed correctly. Incorrect installa-
tion will result in jaws that do not converge evenly
and are unable to securely clamp a workpiece.
Outside Set
Figure 28. Chuck and jaw selection.
Jaws are numbered from 1–3 (see Figure below).
The number is typically stamped on the side or
bottom. Jaws are designed to be installed coun-
terclockwise in numerical order in the matching
numbered jaw guides, so they will hold a concen-
tric workpiece evenly.
Jaw Numbers
Figure 29. Jaw guide and jaw numbers.
-34-
Inside Set
Jaw Guides
To change jaw set:
1. DISCONNECT MACHINE FROM POWER!
2. Use appropriate device to protect ways (refer
to Installation & Removal Device subsec-
tion).
3.
Insert chuck key and turn it counterclockwise
to back jaws out and remove them individu-
ally in descending order (i.e., 3, 2, 1).
4.
Use mineral spirits to clean debris and grime
from jaws and chuck jaw guides.
5.
Apply thin coat of NLGI #2 grease to surfaces
of removed jaw set. Store in safe place free
from moisture and abrasives.
6.
Rotate chuck key clockwise until you see tip
of outer scroll-gear lead thread about to enter
a jaw guide (see below).
Lead Thread
Figure 30. Lead thread on scroll gear.
7. Insert jaw #1 into jaw guide #1 and hold jaw
against scroll-gear.
8. Rotate chuck key clockwise one turn to
engage tip of scroll-gear lead thread into jaw.
Pull jaw; it should be locked into jaw guide.
9.
Install remaining jaws in numerical order, in
the same manner. The jaws should converge
evenly at center of chuck.
— If jaws do not converge evenly, remove
them. Check that jaw numbers and jaw
guides match. Re-install jaws sequentially
1–3, making sure each one engages with
scroll-gear lead thread during its first rota-
tion.
Model G0768/G0769 (Mfd. Since 8/15)