– 7 –
Adjustment procedures
Results of Improper adjustment
1) Returning amount of the lower looper
Loosen clamping screw
❷
of lower looper support arm
❶
and ad-
just lower looper
❸
to make adjustment of the returning amount.
2) Clearance between the lower looper and the needle
1. Loosen clamping screw
❷
of lower looper support arm
❶
to the
extent that it is temporarily tightened.
2. Turn fine-adjustment screw
❺
to adjust the clearance by moving
lower looper support arm
❶
back and forth.
Turn fine-adjustment screw
❺
clockwise to move lower looper
❸
away from the needle
❹
. Turn it counterclockwise to move lower
looper
❸
closer to the needle
❹
.
o
Excessive returning amount of
the lower looper tends to cause
stitch skipping when filament
thread is used.
o
Insufficient returning amount of
the lower looper tends to cause
needle thread stitch skipping
when spun thread is used.
o
Excessive clearance will often
cause needle thread stitch skip-
ping.
o
Insufficient clearance will cause
needle breakage due to the con-
tact of the looper with the needle
❹
, or produce scratches on the
blade point of the looper, leading
to needle thread breakage or
other troubles.
