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If the knives are blunt, they will cause the fabric to pucker and uneven stitches.
NOTE: (a) If one strand of thread can be cut off in front of or at the rear of the knife, the knife is sharp
enough.
(b) When the knives are blunt, replace them with new ones in the manner mentioned below. But be
sure to disconnect the power first.
1. Replacing the upper knife
(1) Loosen the upper knife set screw, pull up the upper knife and remove it.
(2) Insert the new upper knife into the upper knife holder.
(3) Then turn the handwheel until the upper knife is lowered.
(4) When the upper knife is at its lowest point, the distance (in the front-to-back direction) from the top of
the blade farthest forward of the lower knife should be 1.2 ~ 1.7 mm from the position farthest forward
of the upper knife.
(5) Re-tighten the upper knife well. Securely tighten the upper knife set screw.
2. Replacing the lower knife
(1) Loosen lower knife set screw and remove lower knife.
(2) Attach new lower knife on lower knife holder, and set position so that point of knife is the same level
as upper surface of needle plate. Tighten it with lower knife set screw.
NOTE: It is important to adjust the alignment of the upper and lower knives to enable sharp cutting.
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