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WARNING :
Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine.
Trouble
Cause (1)
Cause (2)
Checking order and adjusting procedure
21. Puckering (Mainly concerned
with double chainstitch)
21-1) Needle
1-A)
The needle is too thick.
Use a thin needle as much as possible.
21-2) Thread
2-A)
The thread used is too thick.
Use a thin thread as much as possible.
21-3) Thread tension
3-A)
Both the needle thread and looper
thread tensions are too high.
Reduce the both thread tensions to a minimum.
21-4) Throat plate
4-A)
The throat plate has a large needle
hole.
Replace the throat plate with one with a small
needle hole.
21-5) Thread cam timing
5-A)
The thread cam timing is too late.
Advance the cam timing. Refer to the pertinent
Standard Adjustment.
21-6) Feed dogs
6-A)
The leading edge of the feed dog teeth
has been rounded off.
Replace the feed dog.
6-B)
A difference in level exists between the
main feed dog and differential feed dog.
Eliminate such difference in level.
21-7) Presser foot pres-
sure
7-A)
The presser foot pressure is not high
enough, providing poor ironing effect.
Increase the presser foot pressure.
21-8) Differential feed
ratio
8-A)
The differential feed ratio has been set
for gathering.
Set it for stretching. When stretching light-weight
materials, be careful not to cause the presser foot
to contact unevenly with the materials.
21-9) Thread amount
9-A)
The looper thread amount is not
enough, causing excessively tensed
stitches.
Bring the thread cam thread guide fully to the
front to increase the amount of looper thread.
