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6
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TIMING OF THE LOOPERS TO THE NEEDLES
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Timing of the looper to the needle is factory-set properly.
However, when disassembling the needle bar mechanism, looper mechanism or using a
new part, this timing should be readjusted. Refer to the following procedures.
6-1 To adjust the timing
1.
Remove the needle, needle plate, presser foot, feed
dog and auxiliary feed dog and feeding roller.
2.
Remove the front looper. Then install test bar A
(diameter : 3.97). Tighten screw B.
3.
With the looper holder at the extreme right end of
its travel, position test bar A so that it is normal to
the throat plate. Adjustment is made by
loosening screw C and positioning the looper
holder again.
4.
Bring test bar A to the extreme left end of its
travel. Then install the needle plate.
5.
Turn the machine pulley counterclockwise slowly
until the test bar touches slightly the needle plate.
6.
Fit timing gauge D onto the underside of the
machine head. Then secure it on the needle bar.
7.
Turn the machine pulley clockwise slowly until
timing gauge D touches the machine head or test
bar A touches the needle plate.
Clearance between timing gauge D and the
machine head or test bar A and the needle plate
should be within 0.1mm. If it is, the timing will
be correctly achieved. If it is more than 0.1mm,
follow the procedures below.
8.
Remove the cover of the crank chamber and
packing. Loosen screws F of joint collar E.
If timing gauge D touches the machine head before
test bar A touches the needle plate while the
machine pulley is turned slowly clockwise, the
looper timing is fast. Therefore fix the crankshaft
and turn main shaft G clockwise.
If test bar A touches the needle plate and there is a
clearance between timing gauge D and the
machine head, the looper timing is slow.
Turn main shaft G counterclockwise.
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Every time joint collar E is readjusted, perform 6, 7 and
8 procedures repeatedly.
To do so, tighten any one of screws F temporarily.
After the adjustment has been achieved, tighten screws
F securely. Then make sure the correct timing is
obtained by referring to the above procedures.
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