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20. Adjusting the alternating amount of presser foot (Fig.18)
When the presser foot is alternating increasingly,
adjust it upward in the range of the long hole of the
top feed crank ③; when the presser foot is alternating
decreasingly, adjust it downward, then tighten the
nut ②.
When the lifting amount of the presser and walking
foot is different, first align the bottom of the presser
foot and walking foot with the surface of the needle
plate, then loosen the set screw ①.Turn the balance
wheel to the front, the lifting amount of the presser
foot is more than that of the walking foot. Turn the
balance wheel reversely, the lifting amount of the
walking foot is more than that of the presser foot.
Finally tighten screw ②
Remove the right side of the window plate, then the
top feed crank ③ can be observed.
21. Sewing speed list
Altenating amount
Less than 3mm
Between 3~4mm
Between 4~6.5mm
22. Troubleshooting
Trouble
1. Thread breaking (2-3mm
thread left on the cloth)
2. Puckering
3. Loose stitch
Stitch less than 6mm
2500s.p.m
2000s.p.m
1600s.p.m
Possible cause
1. Damage on the rotating hook set
groove of thread way, needle point,
rotating hook point and needle plate.
2. Too strong the needle thread tension
3. Collision between needle and rotating
hook.
4. Too little the oil of the rotating hook
5. Too weak the needle thread tension.
6. Too strong the tension of the threaad
take-up spring
7. Over fast or slow the timing between
needle and rotating hook
1. Over fast or slow the timing between
needle and rotating hook.
2. Too weak the pressure of the presser
foot.
3. The clearance between the up end of
the needle and the rotating hook is not
right.
4. Wrong needle.
1. Without threading the bobbin thread
under the spring of the thread tension
of the rotating hook body.
2. Bad work on thread way.
3. No movement of bobbin.
4. Too weak the bobbin thread tension.
5. Too strong the bobbin thread tension.
6. Damage of the needle point.
7
②
Stitch length between 6mm-9mm
2000s.p.m
2000s.p.m
1600s.p.m
Remedy
1. Polish the damaged part with sand
paper; rasp the middle rotating hook set
groove with file.
2. Weaken the needle thread tension.
3. Refer to (19.Relationship between
needle and rotating hook.)
4. Adjust the oil amount (Refer to7.
Lubrication)
5. Increase the needle thread tension.
6. Weaken the tension of the thread
take-up spring.
7. Refer to (19. Relationship between
needle and rotating hook)
1. Refer to (19. Relationship between
needle and rotating hook).
2. Tighten the pressr foot adjusting
screw.
3. Refer to (19.Relationship between
needle and rotating hook.)
4. Replace the needle.
1. Refer to (9.Threading the bobbin
thread)
2. Rast with sand paper or file.
3. Replace the bobbin or rotating hook
4. Increase the bobbin thread tension.
5. Reduce the bobbin thread tension.
6. Replace the needle.
18
①
③
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