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7. Poorly tense stitches
7-1) Tension controller AT is
1-A) Tension of the tension controller
Properly adjust the tension of tension controller AT.
maladjusted.
AT is low.
7-2) Tension controller AT is
Adjust the thread tension releasing mechanism.
floating.
7-3) Thread take-up spring is
Adjust thread take-up spring tension and stroke.
maladjusted.
7-4) Clearance between the inner
4-A) The clearance between the
Properly adjust the clearance of inner hook and
hook and the shuttle driver is
inner hook and the shuttle
shuttle driver.
defective.
driver is too small.
7-5) Selection of the needle to be
5-A) Needle to be used is thin.
Replace the needle with a thicker one.
used is improper.
7-6) Selection of the needle hole
6-A) Hole diameter of the needle
Replace the needle hole guide with a new one having
guide is improper.
hole guide to the needle to be
a larger needle hole.
used and thread is small.
7-7) Shape of the feed plate is
7-A) Material to be sewn is stiff and
Raise the material to be sewn by means of the feed
defective.
closely contacted with the throat
plate.
plate, and there is no clearance
between them to pass the thread.
7-B) Material to be sewn is highly
Raise the material to be sewn by means of the feed
elastic and closely contacted
plate.
with the throat plate, and there
is no clearance between
them to pass the thread.
7-8) Feed timing is defective
8-A) Feed timing is too fast.
Use the memory switch to change the feed timing.
Trouble
Cause (1)
Cause (2)
Check and corrective measures
