2. Looper thread breakage
Thread path
Scratches, burrs, rust, etc, on the paw of
Remove such scratches, burrs, etc. and carry
the throat plate, stitch tongue, looper,
out thread path finishing. Replace loopers or
looper thread take-up, thread guide,
other components which have been deformed,
or tension discs causes friction.
causing thread breakage.
Adjustment of the looper thread take-up
The looper thread take-up or thread guide
Refer to the pertinent Standard Adjustment.
36
has been improperly positioned, causing
excessive thread tension.
Thread tension
The looper thread tension is too high.
Reduce the tension while checking the tension
balance other looper thread.
Thread
The thread is weak because of its poor
Replace the thread by one with good quality.
quality.
Position of the thread guides
The upper looper thread guide is too high,
Refer to the pertinent Standard Adjustment.
36
(only for double chain stitch)
and the thread taking balance is disturbed,
resulting in the thread breakage.
Double chain looper avoid
The double chain looper strikes the needle
Correct the longitudinal motion of the double
16
at the back, causing the thread breakage.
chain looper so as not to cause the looper to
strike the needle.
Needle heat
The needle gets hot, and the looper thread
Refer to the clause relating to the needle heat
breaks when it comes in contact with the
causing needle thread breakage.
hot needle at the time of needle stop.
Trouble
Case (1)
Case (2)
Check and Corrective measures
Page
3. Needle breakage
Needle entry
The needle entry has not been correctly
Correct the needle entry.
4
adjusted, and the needle strikes the throat
plate or presser foot.
Upper looper position
The upper looper juts out too much or
Refer to the related Standard Adjustment.
14
it is too low.
Contact with the looper
The needle strikes the looper, resulting
Re-position the looper so that it does not come
in needle breakage.
in contact with the needle. Adjust the longitudinal
motion of the double chain looper for the contact
of its back with the needle.
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Summary of Contents for MO-6700D Series
Page 49: ...45 2 Upper looper components...
