JUKI MO-6000S series Engineer's Manual page 15

Adjustment Procedures
1) Loosen setscrew 3 and adjust, by slightly turning needle clamp
4, the clearance provided between the right-hand side needle
and the lower looper (for 2-needle overlock machine) and the
clearance provided between the needle hole in the throat plate
and the needle (for safety stitch machine).
1) Loosen setscrew 1 of the lower looper holder from the rear of
the frame.
Since it is difficult to accurately measure the center-to-center
distance, perform adjustment to provide a 3.5 mm distance
between the end surface of the arm and the neck of the ball as
illustrated.
Results of Improper Adjustment
™ If the clearance provided
between the needle and the
looper is excessive, the needle
thread will be likely to skip at the
time of tucking.
™ If the clearance provided
between the needle and the
looper is insufficient, the needle
will break or the looper blade
point will be damaged causing
thread breakage.
™ Increasing the center-to-center
distance will give a smaller
stroke of the duble chain looper
or lower looper, and decreasing
the distance will give larger
stroke.
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