5-21
4) Relationship between Needle and Hook
①
Adjusting Timing between Needle and Hook
Default timing of the needle and the hook is set by the main shaft angle of 201
�
and varies as below.
②
Adjusting Gap between Needle and Hook Point
�
Gap between the hook point and the scarf of the needle
should be 0.1-0.3 mm minimum.
�
Thread skip occurs due to thread looping or inadequate
balance/gap between the needle and the hook. The closer the
hook point is to the needle, the hook point will be inside the
loop and threading will be more stable.
[Fig.5-26]
[Fig.5-28]
Hook point
0.1~0.3mm
[Fig.5-27]
Top edge of
needle eye
Top point of hook
circumference
Needle tip
c
b
a
Top edge of the
needle eye
Hook allowance
(gap)
Hook
point
Lower dead stop
of the needle
Hook point
a. At lower dead stop of the needle bar
2.3~3.7 mm
1.8~2.2 mm
0.5~1.5 mm
The figures may change according
to needle specification/number.
b. At needle-hook timing
c. At needle-hook timing
[CAUTION]
The hook can move right and left if there is an allowance
in the lower shaft gear. Eliminate the allowance (gap) by
turning the hook clockwise. Then adjust the timing.
