JUKI MO-6700D Series Manual page 19

Adjustment Procedure
1
1) Height of the upper looper
Set a hexagon wrench key onto setscrew
2
bracket to adjust height
When adjusting the height, pay attention also to the clearance pro-
duced between the upper looper and lower looper
their crossing.
1
2) Longitudinal position of the upper looper
Loosen setscrew
upper looper back or forth for positioning the clearance of 0.05 to
0.2 mm between upper looper
their crossing or the clearance of 0.01 to 0.2 mm between upper looper
and needle .
.
D
at the top end of upper looper bracket
and lower looper
at the end of upper looper
at the time of
to move
at the time of
– 15 –
Results of Improper Adjustment
o If the upper looper has been
positioned too high, an 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.
o On the contrary, if the upper
looper has been positioned too
low, the needle point will hit the
looper, causing needle break-
age. Also the looper will touch
other component when the
presser foot goes up.
o Excessive clearance will cause
stitch skipping.
o Insufficient clearance will cause
the upper looper to come in con-
tact with the lower looper.