SunStar HC Series - Page 60

Error Type Cause
Bad thread (weak,
uneven thickness, poorly
twisted, old)
Right-twisted thread
Excessive thread tension
Tension imbalance
between upper and lower
threads
Excessive tension & stroke
on take-up spring
Inspection & Repair
Change thread
Change to left-twisted thread
Adjust tension
Adjust tension and stroke
Check the using thread
Selecting thread
soft, even thickness
tight, left-twisted
Z-direction: left
S-direction: right
(CAUTION)
left-twist prevents unraveling
in the counterclockwise
rotation of the hook
Reference