JUKI MF-7900 Series Engineer's Manual page 37

Adjustment procedures
Loosen setscrew ❷ in the looper holder and move looper hold-
1.
er ❸ to the right and left for adjust.
After the adjustment, tighten setscrew ❷ in the looper holder.
2.
(Caution) When adjusting looper holder ❸ , check the longitu-
dinal position of looper ❶ after adjusting the lateral
position since looper holder ❸ rotates to and fro and
moves.
3. Longitudinal position
Adjust so that the clearance provided between blade point B
of looper ❶ and left needle ❹ is 0 to 0.05 mm when the top
end of looper ❶ comes to the center of left needle ❹ from the
extreme right position.
After the adjustment, fix the looper holder with setscrew ❷ in
the looper holder.
* Blade point B of the looper ❶ comes in contact with the right
needle when rear needle guard ❻ fails to work. So, be careful.
Results of Improper adjustment
◦ When the returning amount is
large, loop of needle thread
becomes 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.
◦ 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.
– 23 –