JUKI MF-7800D Series, Engineer'S Manual

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1. Loosen setscrew in the looper holder and move looper holder
to the right and left to adjust.
2. After the adjustment, tighten setscrew in the looper holder.
(Caution) When adjusting looper holder , check the longitudinal
position of looper after adjusting the lateral position
since looper holder rotates to and fro and moves.
3. Longitudinal position
Adjust so that the clearance provided between blade point of
looper and left needle is 0.05 to 0.1 mm when the top end of
looper comes to the center of left needle from the extreme right
position.
After the adjustment, fix the looper holder with setscrew in the
looper holder.
* Blade point of the looper comes in contact with right needle and
middle needle when rear needle guard fails to work. So, be careful.
o When the returning amount is
large, loop of needle thread be-
comes large and it is apt to fall.
As a result, stitch skipping or
thread breakage will be caused,
and stitch skipping on the back
is apt to occur.
In addition, thread tangling will be
caused.
o When the returning amount is
small, loop of needle thread is
small and stitch skipping or
thread breakage will be caused.
In addition, thread tangling will be
caused.
Adjustment Procedure Results of Improper Adjustment