SunStar SWF/B Series User Manual page 39

4) Relationship between Needle and Hook
① Adjusting Timing between Needle and Hook
Timing between the needle and the hook is set by the main shaft angle of 200° and varies as below.
Upper point of hook circumference
Top edge of
needle eye
a. At lowest point of needle stroke
b. At needle-hook timing
c. At needle-hook timing
[ CAUTION ]
The hook can move from right and if there is an allowance
in left the lower shaft gear. Adjust the timing after
eliminating the allowance (gap) by turning the hook
clockwise.
② Adjusting Gap between Needle and Hook Point
• Gap between the hook point and the scarf of the needle
should be between 0.1-0.3 mm.
• Thread skip occurs due to thread looping or inadequate
balance or gap between the needle and the hook. If the
hook point is closer to the needle, the hook point will
be inside the loop and threading will be more stable.
Hook point
Top edge of needle eye
Needle tip
Lowest point of
needle stroke
2.3~3.7 mm
1.8~2.2 mm
0.5~1.5 mm
The figures may change according
to specification/number of the
needle.
Gap of Hook
Hook point
0.1~0.3mm
Hook point
[Fig. 5-26]
[Fig. 5-27]
[Fig. 5-28]