Backlash Between Hook Drive Gear And Lower Shaft Gear - Janome MC8900 QCP Service Manual

Backlash between hook drive gear and lower shaft gear

The rotary play of the hook should be 0.8 mm or less when the tip of rotary hook is within the width of feed dog.
Width of feed dog
Lower bushing of the front side
Hexagonal
socket screw (C)
Lower shaft bushing
groove
B
Mechanical adjustment
Tip of rotary hook
0.8 mm or less
Lower shaft gear
Hook driving gear
A
Lower shaft gear
1. Remove the base cover and bed cover (see page 2 and 3).
2. Remove the presser foot, the needle plate and the bobbin
holder. (see page 4)
* Cover the needle plate with the fabric to prevent
damaging the needle plate when removing.
3. Turn the handwheel toward you so the the tip of the
rotary hook is within the width of feed dog as shown in
figure 1.
Check the rotary play of the hook.
4. If the backlash is too much or too little, loosen the
hexagonal socket screw (C) and (D) and following the
adjustment procedure.
If the backlash is too great (more than 0.8 mm), turn the
both lower shaft bushings in direction A. If the
engagement of gear is too tight, and the machine does
not turn smoothly, ) turn the both lower shaft bushings in
direction B.
Adjust the grooves of the lower shaft bushing as well.
5. Tighten the hexagonal socket screws.
Lower bushing of the belt cover
groove
Lower shaft bushing
20
Hexagonal
socket
screw (D)