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Model G8688 (Mfg. 3/09+)
-19-
Changing jaws on the 3-jaw chuck is straight for-
ward, but attention must be paid to the sequence
in which the jaws are loaded into the chuck.
To replace the jaws:
1. UNPLUG THE LATHE!
2. Remove all of the jaws on the chuck by turn-
ing the chuck key counterclockwise.
3. Examine the inside of each slot in the chuck
for debris and clean.
4. Each jaw will be numbered 1,2,3 or A,B,C.
Numbers can be found in the slot, at the bot-
tom of each jaw.
5. Locate jaw #1.
6. Insert the chuck key into the chuck.
7. Turn the chuck key clockwise while looking
straight into the face of the chuck. Notice
the beginning of the lead thread on the scroll
come into view through the slot in a counter-
clockwise direction (see Figure 15).
8. Insert jaw # 1 into this slot then continue to
turn until the jaw is engaged with the lead
thread.
9. Repeat these steps for Jaw #2 then Jaw #3.
It is important to follow these points when replac-
ing jaws in your 3-jaw chuck:
• The jaws must be loaded in sequence begin-
ning with the #1 jaw.
• The chuck, scroll, and jaws should be thor-
oughly cleaned before assembly. (A paint
brush works great for cleaning the scroll).
• Never use a combination of inside and out-
side jaws to hold a workpiece.
• DO NOT over-tighten the chuck jaws. Damage
will occur, resulting in loss of accuracy.
• DO NOT load the jaws into chuck incorrectly
to do eccentric work. Use a 4-jaw chuck for
this purpose.
• 3-jaw chucks will always have a little run-out.
It is advisable to measure the run-out of a
workpiece after it is mounted in the chuck.
If a higher degree of accuracy is desired,
replace the 3-jaw chuck with a 4-jaw chuck
and adjust the workpiece while using a dial
indicator until the desired concentricity is
achieved.
Replacing Chuck
Jaws
Figure 15. Lead thread.