Beisler 739-23-1 Service Manual - Manual (Page 8)

2.5 Loop stroke and distance between hook tip and needle
Caution! Risk of injury!
Switch off main switch!
Adjust loop stroke and distance of the hook tip to the needle only when
the sewing machine is switched off.
Instruction and inspection
The loop stroke is the way the needle bar completes from the lower
dead centre to the point where the hook tip is positionled at the centre
of the needle.
The loop stroke is 1.8 mm.
When the sewing machine is locked in position A, the hook tip 6 is to
stand on the centre of the needle.
The distance between the hook tip 6 and needle must be 0.1 mm.
–
Lock machine head in setting position A.
– Check position of hook tip to the needle.
Adjustment
–
Remove throat plate..
– Insert new needle.
– Loosen securing screws of hook 5.
The screws are accessed through hole 3.
– Lock sewing machine in position A.
– Align hook tip 6 to the centre of the needle.
The distance between the hook tip 6 and the needle scarf must be
0.1 mm.
In this position, the distance between the hook 5 and the set collar
3 is 0.4 mm.
CAUTION!
If the distance is less than 0.4 mm, the hook drive housing must be
adjusted accordingly
(see chapter 2.6).
– Tighten securing screws of hook 5.
– Replace throat plate.
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5
6
1
3
2
4