JUKI MO-6800S Series Engineer's Manual page 19

Adjustment procedures
1) Returning amount of the lower looper
Loosen clamping screw ❷ of lower looper support arm ❶ and ad-
just lower looper ❸ to make adjustment of the returning amount.
2) Clearance between the lower looper and the needle
1. Loosen clamping screw ❷ of lower looper support arm ❶ to the
extent that it is temporarily tightened.
2. Turn fine-adjustment screw ❺ to adjust the clearance by moving
lower looper support arm ❶ back and forth.
Turn fine-adjustment screw ❺ clockwise to move lower looper ❸
away from the needle ❹ . Turn it counterclockwise to move lower
looper ❸ closer to the needle ❹ .
Results of Improper adjustment
Excessive returning amount of
o
the lower looper tends to cause
stitch skipping when filament
thread is used.
Insufficient returning amount of
o
the lower looper tends to cause
needle thread stitch skipping
when spun thread is used.
Excessive clearance will often
o
cause needle thread stitch skip-
ping.
Insufficient clearance will cause
o
needle breakage due to the con-
tact of the looper with the needle
❹ , or produce scratches on the
blade point of the looper, leading
to needle thread breakage or
other troubles.
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