Singer 321C 131M-04 Instruction Manual page 21

Possible Causes
1- Wrong threading.
2- Wrong installation of thread stand.
3- Wrong setting of lower knfe.
4- Knives does not cut perfectly.
5- Thread guide or tension disc with burrs.
6- Needle point damaged.
Z Inadequate height of feed dog.
8- Inadequate thread tension.
Thread tension is too strong.
Inadequate pressure on presser foot.
Inadequate height of feed dog.
Knives does not cut perfectly
Difierential feed is not correct.
Needle is too thick.
Incorrect presser foot.
Inadequate synchronism of Iopper cam.
Chain stitch Iooper installed wrongly.
Wrong passage of thread.
Thread tension inadequate.
5- Wrong relation of needle with looper.
Z Needle plate or presser foot with burr.
8- Rough thread tension disc.
High Speed Overlook Machine | Instructions Manual and Parts List
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