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1) Height of the upper looper
1
Set a hexagon wrench key onto setscrew at the end of upper looper
bracket to adjust height
D
.
2
When adjusting the height, pay attention also to the clearance pro-
duced between the upper looper and lower looper at the time of
their crossing.
2) Longitudinal position of the upper looper
1
Loosen setscrew at the top end of upper looper bracket to move
upper looper back or forth for positioning the clearance of 0.05 to
0.2 mm between upper looper and lower looper at the time of
their crossing or the clearance of 0.01 to 0.2 mm between upper looper
and needle .
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.
Adjustment Procedure Results of Improper Adjustment
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