Model G0746/G0749 (Mfg. Since 3/13)
-37-
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.
figure 39. Chuck and jaw selection.
Inside Set
Outside Set
figure 40. Jaw guide and jaw numbers.
Jaw Guides
1
2
3
Jaw Numbers
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 in
numerical order in the jaw guides, so they will hold
a concentric workpiece evenly.
To change the jaw set:
1. disCoNNECt lathE FroM poWEr!
2. place a piece of plywood over the bedways to
protect them from potential damage.
3. insert the chuck key and turn it counterclock-
wise to back the jaws out and remove them.
4. Use mineral spirits to clean the debris and
grime from the jaws and chuck jaw guides.
5. apply a thin coat of white lithium grease to
surfaces of removed jaw set. store in a safe
place free from moisture and abrasives.
6. rotate chuck key clockwise until you see
the tip of the scroll-gear lead thread begin to
enter a jaw guide (see
figure 38).
Lead Thread
1
figure 41. lead thread on scroll gear.
7. insert jaw #1 into the jaw guide and hold the
jaw against the scroll-gear.
8. rotate the chuck key clockwise one turn to
engage the tip of the scroll-gear lead thread
into the jaw. pull the jaw; it should be locked
into the jaw guide.
9. install the remaining jaws in numerical order,
in the same manner.
— if installed correctly, the jaws will converge
evenly at the center of the chuck.
— if the jaws do not converge evenly, remove
them. re-install the jaws sequentially 1–3,
and make sure each one engages with the
scroll-gear lead thread during its first rota-
tion.
