JUKI МН-481 Instruction Manual page 31

Tension guage
Moving knife mounting plate
2. Positioning the moving knife
The position of the moving knife is determined by those of the moving knife base, moving knife base mounting
plate and the stopper.
Adjusting screws
Moving knife
0.1 to 0.5 mm
Thread spreader
Looper
– 21 –
Adjustment of the clamping pressure
The looper thread clamping pressure applied by the
thread clamping spring is always constant regardless
of the type of sewing threads, which you need not to
change. If the looper thread is not clamped correctly,
you must replace the moving knife assembly. When a
cotton thread No.60 is clamped and is pulled away as
shown in the illustration, the correct tension is between
70 and 100g. The top end of the spring and the bottom
surface of the moving knife must evenly engage with
each other. Do not change the thread clamping pressure
since it has been properly factory-adjusted at the time
of delivery.
Lateral position of the moving knife base
Adjust it within a range provided by the oval screw
holes.
If you move it to the right, the length of thread remain-
ing on the needle is increased.
Longitudinal position of the moving knife base
Provide a clearance of 0.1 mm to 0.5 mm between the
moving knife and the thread spreader so that the knife
does not hit the spreader when the former approached
to the latter.