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1. Thread breakage
1-1) Threading
1-A) Thread jamming at thread guide,
Refer to "6. How to conduct threading".
threading error
1-2) Thread path
2-A) Resistance is developed when
Remove the scratch, burr, or rust and finish the thread path.
there is a scratch, a burr, or rust
However, replace the old parts with new ones if the parts
ron the throat plate stitch tongue,
are important and the shapes of the parts are changeable
upper fancy looper, fancy thread
such as lower looper and throat plate stitch tongue.
carrier, lower looper, needle damper
thead path section, needle thread
rocking path, needle, upper and
lower fancy thread guides, or thread
tension disc.
1-3) Rear needle guide
3-A) If contact between the needle and
Replace the needle, and replace the part if the rear needle
rear needle guide is excessive, needle
guide is worn.
grooves are created on the rear needle
guide, resulting in thead cut.
1-4) Needle
4-A) The needle is too thin for the thread
Use an appropriate needle.
that is now used.
1-5) Needle heat
5-A) Thread cut occurs because of
Use a thinner needle, or reduce the sewing speed. Use the
heated needle depending on the
silicone oil lubricating unit.
material type, the number of
superimposed materials, and
sewing speed.
1-6) Thread
6-A) Poor quality of the thread
Use a high-quality thread.
1-7) Thread tension
7-A) Excessive thread tension
Reduce the thread tension. The tension is too strong be-
cause the needle thread guide bar is placed too low.
1-8) Contact
8-A) The lower looper touches the feed
Set the lower looper in the proper position.
dog or throat plate because of an
improper lower looper position.
The looper touches the rear needle
guide because of insufficient looper
return.
1-9) Problems with chain-off thread
9-A) The positions of upper fancy looper
Set the parts in the proper positions. Remove the scratch.
or fancy thread carrier is not proper.
The mouting angle of the lower looper
is not proper. There is a scratch on
the throat plate stitch tongue, feed
dog, or small presser.
Trouble
Cause (1)
Cause (2)
Check and corrective measures
12. Troubles and corrective measures
From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
