JUKI LK-1900AN, Engineer'S Manual

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Adjustment procedures Results of Improper adjustment
1. Counter knife position
Loosen the counter knife set screw
1
to adjust the position.
2. Moving knife position
Loosen the screw
2
to adjust the position.
(Caution) 1. In normal operation, the moving knife
8
passes inside the needle hole guide
6
, as il-
lustrated in
A
.
2. The needle plate
4
is the appropriate item for
the LK-1900AN series (40006721).
o
If the clearance is less than 0.5
mm, thread may be cut by the
counter knife
5
blade when the
thread is pulled with the moving
knife
8
. In this case, upper and
lower threads are cut into short
pieces.
o
If the clearance is more than 0.5
mm, the residual thread length
after thread trimmer operation
becomes longer beneath the
work.
Adjustment procedures Results of Improper adjustment
1. Adjustment of the height of the moving knife
Adjustments should be based on the plate thickness of the
washer
3
in the above illustration. If the height seems to be
inadequate, select and use the parts as specified below.
Part No. Name of part Thickness
B242328000A Moving knife washer 0.4 mm
B242328000B Moving knife washer 0.5 mm
B242328000C Moving knife washer 0.6 mm
B242328000D Moving knife washer 0.7 mm
B242328000E Moving knife washer 0.8 mm
2. Adjustment of the height of the counter knife
Adjust the height by prying Part
A
with a screwdriver or the
like.
o
If the step is too small (0.25 to 0.3
mm) between the moving knife
8
and counter knife
5
, trouble
in thread trimmer may occur.
o
If the step is too large (0.1 to 0.15
mm) between the needle hole
guide
6
and the counter knife
5
, thread may be cut by the
counter knife
5
blade when the
thread is pulled with the moving
knife
8
. In this case, upper and
lower threads are cut into short
pieces.