Table of Contents
Advertisement
Trouble
From the previous page
5. Needle thread breakage
The needle thread splits finely or
breaks during sewing.
To the next page
Cause (1)
4-4) The sewing speed is too high.
4-5) The feed timing is inappropri-
ate. (Needle bent)
4-6) The thread take-up spring is
inappropriately adjusted.
4-7) The material is inappropriate-
ly stretched.
5-1) The thread path (including
the throat plate and foot) is
defective.
5-2) The tension of the needle
thread is inappropriate.
Cause (2)
5-A) The needle is bent by the thick
portion.
6-A) The stroke of the thread take-
up spring is too long.
6-B) The tension of the thread take-
up spring is too high.
7-A) The presser is floating.
7-B) The needle hole of the throat
plate is too large.
7-C) The thread relief on the back
side of the presser is too large.
7-D) The parallel level of the presser
is inappropriate.
1-A) The thread path is not smooth.
1-B) The thread path has a flaw.
1-C) The thread path has an obsta-
cle.
2-A) The tension of the needle
thread is too high or too low.
2-B) The 1st thread tension is too
low.
Check and corrective measures
Reduce the sewing speed.
Hasten the feed timing.
Shorten the stroke of the thread take-up spring.
Reduce the tension of the thread take-up
spring.
Adjust the clearance between the presser bar
holder and lifting plate.
Use one with a smaller needle hole.
Use one with a smaller relief or with no relief.
Replace the presser, or loosen the presser bar
holding screw and correct the foot bend.
Finish the thread path appropriately.
Finish the thread path appropriately.
Check threading again and conduct correction
if necessary.
Adjust the tension of the needle thread to the
appropriate level.
Adjust the tension of the needle thread to elimi-
nate random movement of the thread between
the 1st and 2nd thread tension portions.
Advertisement
Table of Contents
