JUKI MB-1373 Engineer's Manual page 7

Adjustment Procedure
1. Depress the pedal fully forward, turn the needle driving pulley in the
normal sewing direction by hand to bring down the needle bar to
the lowest position of its stroke and loosen screw
2. Adjust the height of the needle bar using the top two lines engraved
on needle bar for the TQx1 needle and using the bottom two
lines for the TQx7 needle. Align upper line
face of needle bar bushing (lower)
time, tighten the screw so that groove
front.
Adjustment Procedure
1. Adjusting the looper timing
Loosen two screws
cam and looper sleeve in the rotating direction so that the looper
blade point aligns with the center of the needle when the lower
engraved lines on the needle bar are aligned with the bottom of
lower bushing . Then, tighten screws
2. Clearance between the needle and looper
Loosen two screw
point of the looper aligns with the center of the needle. Adjust so
that a clearance of 0.01 to 0.1 mm is provided between the looper
and needle. Then, tighten setscrew
3. Clearance between the needle guide and needle
Loosen setscrew
Adjust so that a 0.05 to 0.1 mm clearance is provided between needle
guide and the needle and tighten setscrew
and tighten screw
of the needle faces the
B
in the cam and looper sleeve. Then turn the
.
in the looper support ring when the blade
.
when the needle bar is in the lowest position.
.
with the bottom end
A
. At this
.
– 3 –
Results of Improper Adjustment
o If needle bar is too high,
skipped stitches will be produced.
o If the needle bar is too low, the
needle will come into contact with
the looper.
Results of Improper Adjustment
o If the clearance between the
needle and looper is too exces-
sive, it is likely to produce skipped
stitches. If the clearance is too
small, in accordance with the ma-
terial used, the needle will come
into contact with the looper, result-
ing in needle breakage and
looper's blade point breakage.
o For thick materials and overlapped
sections, adjust the clearance
between the needle guide
needle so that the needle guide
touches the needle by 0.05 to 0.1
mm.
and