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1) Counter Knife
1. Loosen the set screws
of the counter knife base
.
2. Bring the counter knife
to the position shown in the left figure,
using the counter knife gauge
supplied with the machine. At that
time, adjust the counter knife gauge
so that the section A of the
counter knife gauge
should come in contact with the attaching
groove on the bed slide plate, and the section B should come in
contact with the end face of the throat plate.
3. Move the counter knife gauge base
to adjust so that the counter
knife
comes in contact with the sections C and D of the counter
knife gauge
. Then, fasten the set screws
.
2) Clamp Spring
1. Loosen the set screws
of the clamp spring
.
2. Adjust the clearance between the clamp spring
and the counter
knife
by sliding the clamp spring
along the surface of the counter
knife base
on which the clamp spring
is to be attached. At this
time, adjust the clearance using the sections E and F of the counter
knife gauge
.
3. Thickness of the section E is 1.7 mm and that of section F is 1.5 mm.
Adjust the position of the clamp spring
so that the section E of the
gauge does not smoothly pass through the clearance provided be-
tween the clamp spring
and the counter knife
, but the section F
of the gauge does smoothly pass through it.
4. Fasten the set screws
of the clamp spring
.
3) Knife Pressure
1. When the moving knife
and the counter knife
come in contact
each other, adjust the attaching position of the moving knife
so
that the moving knife
starts coming in contact with the counter
knife
at the position that is 5.5 to 6.5 mm away from the top end of
the moving knife
, by means of loosing the set screw
of the
moving knife
.
4) Moving Knife Driving Arms A, B and C
1. In the case of the right-hand side hook, loosen the set screws of the
moving knife driving arm A
and B
and adjust so that the top
end of the moving knife is 0.5 mm from the top end of the counter
knife. In the case of the left-hand side hook, loosen the set screws of
the moving knife driving arms A
and C
, and adjust in the same
way as in the right-hand side hook.
2. Put the plunger stopper
of the thread trimmer solenoid
onto
the main body of the solenoid
and fasten the clamping screws of
the moving knife driving arms B
and C
.
3. Adjust so that a clearance of 0.2 mm is provided between the thread
trimmer cam
and the thread trimmer cam roller
when the thread
trimmer cam
is brought to the highest position of its stroke (for
both the right-hand and left-hand side hooks).
4. Fasten the clamping screw
of the moving knife driving arm A
.
[Item to be confirmed]
Turn the hand-wheel by hand to make the sewing machine perform thread
trimming and align the top end of the moving knife
with the top end of the
counter knife
, which is the initial position of the thread trimming mechanism.
At this time, make sure that a clearance of 0.05 to 1.5 mm is provided between
the plunger stopper
of the thread trimmer solenoid
and the main body of
the thread trimmer solenoid
.
o If the dimension
A
is larger:
• Knife pressure will be higher. As a
r e s u l t , t h e m o t o r m a y b e
unnecessarily stopped.
o If the dimension
A
is smaller:
• Knife pressure will be lower, result-
ing in thread breakage.
o If the dimension
B
(23.6 mm) is
larger:
• The length of the bobbin thread to
be clamped will be shortened, re-
sulting in stitch skipping.
o If the dimension
B
(23.6 mm) is
smaller:
• Thread trimming failure may occur.
o If the clearance between the clamp
spring and the counter knife is too
large:
• Bobbin thread clamping failure may
result.
o If the clearance between the clamp
spring and the counter knife is too
small:
• The clamp spring may clamp the
needle thread. This means that the
material may not be taken out from
the sewing position with ease. As a
result, the clamped bobbin thread
may be removed together with the
material.
o If the knife pressure is too high:
• The blades of the counter knife
and the moving knife
may break.
o If the knife pressure is too low:
• Thread trimming failure may result.
o If the distance from the top end of the
counter knife to the top end of the
moving knife is larger than the speci-
fied value:
• The moving knife
may overrun
after trimming the thread, resulting
in clamping failure.
o If the distance from the top end of the
counter knife to the top end of the
moving knife is smaller than the speci-
fied value:
• The main body of the solenoid
may interfere with the plunger
stopper at the time of thread trim-
ming.
Adjustment Procedure
Results of Improper Adjustment
