JUKI MF-7800D Series, Engineer'S Manual

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3. Engaging the knives and adjusting the clamp spring
(1) Loosen screws and , and adjust the position of upper knife
so that the engagement of the upper knife with the lower knife is
0.5 mm when lower knife moves to the extreme right.
(2) At the same time, adjust so that the distance from the top end of
clamp spring to that of lower knife is 3.2 mm.
(3) After the adjustment, tighten screws .
4. Adjusting the position of clamp pressure adjusting spring
(1) Loosen screws and adjust the position of clamp pressure adjusting
spring so that the distance from the top end of clamp pressure
adjusting spring to section A of upper knife is 0.5 mm to 1 mm.
(2) After the adjustment, tighten screws .
5. Adjusting the pressure of clamp spring
(1) Looper thread is held by clamp spring after thread trimming.
(2) Holding pressure of the looper thread can be adjusted by turning
screw .
(3) When screw is turned clockwise, the holding pressure is increased
and turned counterclockwise, the pressure is decreased.
(4) Make the holding pressure as low as possible within the range of
holding the looper thread.
Adjustment Procedure
Results of Improper Adjustment
UT25