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9. TABLE OF TROUBLES AND CORRECTIVE MEASURES
(1) With regard to sewing
Troubles Causes Checking Corrective measures
Thread breakage Thread path, needle point, Check the sharp Remove the sharp edges or burrs
hook blade point or inner edge or burr on the on the blade point of hook using
hook resting groove on respective parts. a fine emery paper. Buff up the
the throat plate has sharp groove section on the throat plate.
edges or burrs.
Thread is worn out. Needle thread tension is Adjust the needle thread tension.
too high.
Needle comes in contact Check the clearance. Refer to “(7) Needle-to-hook
with the blade point of timing”
hook.
Clearance of inner hook Check the clearance. Decrease the clearance. Refer to
guide is too large. “(6) Adjusting the inner hook
guide”.
Amount of oil in the hook Check the amount of Adjust the amount of oil in the
is insufficient. oil in the hook. hook. Refer to “(21) Lubrication”.
Trimmed with the tooth Feed dog check Provide a groove behind the
of the feed dog. feed dog needle hole
Alternate vertical Reduce the amount of alternate
movement check vertical movement.
Sewing speed check Reduce the sewing speed.
Needle thread trails 2 Needle thread tension is Adjust the needle thread tension.
to 3 cm from the wrong too low. (This trouble occurs a lot when
side of the fabric. using synthetic threads.
Thread take-up spring Decrease the tension of of the
works excessively or the thread take-up spring and
stroke of the spring is too increase the stroke of the spring.
small.
Feed timing is not proper. Refer to “(9) Feed cam timing”.
Timing between the Check the specified Refer to “(7) Needle-to-hook
needle and the hook is dimension. timing”.
excessively advanced or
retarded.
Thread melts due to Decrease the sewing speed.
needle heat. Use silicon oil. (Refer to * below.)
Amount of oil in the hook Check the amount of Adjust the amount of oil in the
is excessive. oil in the hook. hook. Refer to “(21) Lubrication”.
1
* Use separately available parts below : “21144308 Needle thread lubricator”
“B1114012000 Thread guide rod”
“B91351230B0 Silicon oiler”
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