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Adjustment of main feed dog and differential feed dog
1. For the feed rocking lever eccentric pin of the feed dog, the
standard positioning of the driver groove is horizontal.
If the driver groove seems to be inclined deviating from the standard
positioning, loosen the setscrew and adjust the feed rocking lever
eccentric pin of the feed dog until it assumes its horizontal posture.
Since then, tighten the setscrew .
2. Mount the main feed dog , differential feed dog and throat
plate , and fix the throat plate .
3. In the first place, adjust the height of the main feed dog to the
standard position. Then fix it by tightening the setscrew .
4. Apply the feed dog support to the bottom of the front section of
the main feed dog and tighten the setscrew .
5. Then, adjust the height of the differential feed dog to the standard
position. After that, fix it by tightening the setscrew .
6. According to "(10) Feed adjustments, 1) Adjustment of stitch length",
adjust the maximum feed amount of the main feed dog to 3.6mm.
(Apply a ruler to the side of the main feed dog and confirm the
result by turning the pulley counterclockwise.)
7. Turn the pulley counterclockwise and confirm that there is no contact
between the main feed dog and the feed groove front/rear section
of the throat plate .
If there is any contact, loosen the setscrew of the main feed
rocking lever link and turn the main feed rocking eccentric drive
stud to adjust the throat plate not to contact the feed groove
front/rear section. After adjustments, tighten the setscrew .
8. After the front and rear momentum amount has been adjusted for
the main feed dog , adjust the sewing length to the standard value
of 3.2mm.
(Caution) 1. In the case of front and rear adjustments of the
differential feed dog mechanism, specific attention
should be paid to the fine feed dog section of the
main feed dog .
2. To make front and rear adjustments of the main feed
dog , loosen eight setscrews of the cylinder
cover and remove the cylinder cover set .
After adjustments, mount the cylinder cover set ,
and tighten the setscrews .
3. For the main feed dog and the differential feed
dog , the longitudinal gradients and the
horizontality are kept constant and cannot be
adjusted.
When the height of feed dogs ,
is insufficient
o The amount of feed is decreased
and uneven feeding can occur.
oWhen the height of the rear
needle guide is lowered, this will
cause breakage of a needle or
stitch skipping.
When the height of feed dogs ,
is excessive
o This can be a cause of the
materials pushed back to the front
side, or of giving rise to feed flaws.
oWhen the height of the rear
needle holder is raised and the
margin of the needle contact
position is increased, this will
cause failure in producing loops
and stitch skipping.
Adjustment Procedures Results of Improper Adjustment
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