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59
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Troubles
Cause (1)
Cause (2)
Checking orders and corrective measures
Irregular stitches
Places related to th hook are defective.
Bobbin or bobbin case is defective.
Needle thread or bobbin thread tension is
too low.
Thread take-up spring is improperly
adjusted.
Thread path is defective.
Cloth is floppy.
Looseness in feed movement direction
Stroke of the thread take-up is large.
There is no resistance in the thread guide
rod.
Amount of oil in the hook is too many or
too small.
Defective hook (thread is caught in the
hook, thread path is defective, etc.)
Bobbin thread is caught in the bobbin case
due to the defective engagement of bobbin
with bobbin case.
Bobbin thread is caught in the bobbin case
due to defective thread winding round the
bobbin.
Tension adjusting spring of bobbin case is
defective.
Bobbin thread in the bobbin case runs idle.
Setting direction of bobbin into bobbin case
is improper.
Stroke of thread take-up spring is large or
small.
The tension is high or low.
Thread path is not smooth.
There is a scratch in the thread path.
There is a burr in the thread path.
Needle hole of throat plate is too large.
Recess for thread on the presser foot sole
is too large.
Parallelism of the presser foot is defective.
Presser foot is rising.
Pitch changes according to the number of
revolution and irregular stitches occur.
Properly adjust the amount of oil.
Replace the hook, or correct the thread path.
Replace the bobbin or bobbin case.
Adjust the tension or position of the bobbin winder thread tension.
In addition, take care of uneven winding.
Replace the bobbin case.
Adjust the tension of idle-prevention spring referring to the item
7.
Refer to the item 7. Reverse revolution of the bobbin improves
irregular stitches.
Increase the tension.
Adjust the stroke of the thread take-up spring.
Adjust the tension.
Finish the thread path.
Finish the thread path.
Correct the threading.
Replace it with gauge with small needle hole.
Use the presser foot with small recess on the sole or without
recess.
Replace the presser foot. Or, when the needle entry position is
improper, loosen the presser bar guide brackect screw and correct
the needle entry position or the bend of the presser foot.
Adjust the clearance between the presser bar guide bracket and
the lifting plate.
Check the looseness in the feed driving section and remove the
looseness.
Move the arm thread guide to the right and decrease the supply
of thread from the thread take-up.
Use D1113126WA0.