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56
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Troubles
Cause (1)
Cause (2)
Checking orders and corrective measures
From the previous page
Thread breaks when reverse feed stitching
or back-tack stitching is performed.
Needle is defective.
Places related to the hook are defective.
Places related to the hook are defective.
Attaching direction of the needle is
improper.
Needle is bent.
There is a scratch on the needle.
Top end of the needle is blunt.
Attaching direction of the needle is
improper.
Needle is too thin or too thick for the thread
used.
Top end of the needle is too sharp.
There are scratches on the hook thread
path.
Blade point of the hook is blunt, or worn
out.
Clearance between hook and bobbin case
holder is small.
Amount of oil in the hook is small.
There are scratches on the hook thread
path.
Attching direction of the needle is improper.
Thread take-up spring is improperly
adjusted.
Replace the needle.
Replace the needle.
Replace the needle.
Reattach the needle. Defective stitching is apt to occur when
attaching the needle with its indented part facing to this side.
Replace the needle.
Use the ball-point needle.
Replace the needle.
Correct the hook blade point, or replace the hook.
Increase the clearance to improve the slide of thread.
Properly adjust the amount of oil in the hook.
Replace the needle.
Attach the needle with its indented part facing slightly to anti-
operator’s side (approx. 10˚) from the exact lateral side.
Adjust the thread take-up spring so that thread is not fed from
the thread tension disk before the thread take-up spring moves
to the end of stroke.
(It is effective to adjust the spring pressure to lower, and the stroke
to larger than the specified values.)
Turn thread around the needle, or change the needle bar thread
guide to T-type one (B1418227T00).
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