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Adjustment Procedures
Results of Improper Adjustment
1) Lower knife adjustment
1. Loosen the setscrew
and move the lower knife
to secure the
standard size of 0.8 to 1.6mm. Since then, tighten the setscrew
.
2) Upper knife adjustment
1. Attach the upper knife auxiliary plate
to the knife holder shank
and install the upper knife fixing block
. Since then, tighten the
setscrew
.
2. Turn the hand pulley in forward direction to the leftmost position of
the upper knife driving bracket
. Insert the upper knife
from the
right side of the upper knife fixing block
and tighten the setscrew
after confirming that the standard crossing size of 0.4mm has
been secured in conjunction with the lower knife
.
3. If the right to left angle of the upper knife
seems to be inadequate
for the lower knife
in regard to the meshing condition between the
upper and lower knives
and
, loosen the screw
and change
the angle of the upper knife
.
3) Pressure adjustment of upper knife
1. At the time of crossing of the upper and lower knives
and
,
loosen the setscrew
and measure the distance of 1.6mm between
the upper face of the knife holder shank
of the upper knife driving
bracket
and the lower face of the knife base guide
. After this
distance has been confirmed, tighten the setscrew
.
o According to the right and left po-
sitioning mesh between the upper
and lower knives
and
, the
amount of material stacks is
changed.
o If the knives become blunt,
stitches at the edge of material
cloth become unstable. This can
be a cause of stitch skipping.
o If the spring pressure is too strong
for the upper knife
, the sharp-
ness of the knife will soon be low-
ered.
From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
