99
Thread breaks
⑫
Dent on thread path on
hook and bobbin case
⑬
Narrow space between
hook holder and groove for
hook holder (on hook)
⑭
Insufficient oil in hook
⑮
Poor timing of needle and
hook
⒃
Incorrect lower dead stop
⒔
Dent on thread path
⒕
Fabric moves on the frame
⒖
Inadequate height of
presser foot
(does not press the work
material)
■
Remove dent or change the
case
■
Adjust space
■
Oil the raceway of hook
■
Adjust timing
■
Adjust the lower dead stop
■
Check:
①
Thread path in presser
foot
②
Around needle hole on
needle plate
③
Thread guide on the
head
④
Thread path in tension
adjuster
⑤
Thread path in upper
thread holding unit
■
Fix the material firmly
■
Adjust height
■
Check rotary hook
■
Set it at 0.5-0.7mm
for smooth feeding of
upper thread
■
See 8.2.4) (p.43)
■
See 13.10) (p.85)
■
See 13.6) (p.81)
Inspection & Repair
Cause
Error Type
Reference
0.5~0.7mm
Hook
holder
