JUKI MO-6000S series Engineer's Manual page 23

Adjustment Procedures
1) Height of the upper looper
1 Set a hexagon screwdriver onto setscrew 2 at the end of upper
looper bracket 1 to adjust height D.
2 When adjusting the height, pay attention also to the clearance
produced between the upper looper and the lower looper at
the time of their crossing.
2) Longitudinal position of the upper looper
1 Loosen setscrew 2 at the top end of upper looper bracket 1
to move upper looper 3 back or forth for positioning the
clearance of 0.1 to 0.2 mm between the upper looper and the
lower looper at the time of their crossing or the clearance of 0
to 0.2 mm between upper looper 3 and the needle.
Results of Improper Adjustment
™ If the upper looper has been
p o s i t i o n e d t o o h i g h , a n
excessive clearance will be
produced between the upper
looper and the needle. As the
result, the upper looper thread
will fail to catch the needle
thread, and stitch skipping
occurs.
™ On the contrary, if the upper
looper has been positioned too
low, the needle point will hit the
l o o p e r , c a u s i n g n e e d l e
breakage. Also the looper will
touch other component when
the presser foot goes up.
™ Excessive clearance will cause
stitch skipping.
™ Insufficient clearance will cause
the upper looper to come in
contact with the lower looper.
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