Adjusting The Counter Knife Position And The Knife Pressure - JUKI LH-3500A Series Instruction Manual

6-10. Adjusting the counter knife position and the knife pressure

WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
❷
❶
❹
❶
❺
❸
❷
❶
A
❶
A
❷
❷
❻
A
❷
– 41 –
1) Align counter knife base ❶ with plane A of
counter knife ❷ .
2) Adjusting the knife pressure
1. Tighten setscrews ❸ with counter knife base ❶
and planes A of counter knife ❷ aligned.
2. Loosen setscrew ❹ of counter knife base ❶ .
Adjust the height of the counter knife with eccen-
tric pin ❺ to adjust the knife pressure of counter
knife ❷ adequately.
3. The standard adjustment value of the counter
knife position is obtained by adjusting eccentric
pin ❺ to the position that is reached by turning
eccentric pin ❺ in such a direction as to push
moving knife ❻ (downward) by approximately
10° after counter knife ❷ comes in contact with
moving knife ❻ .
If the counter knife pressure is too high :
・ The thread will be trimmed easily, but the
counter knife will wear off quickly.
・ Operating load of the moving knife will
increase resulting in, sometimes, thread
trimming failure due to the moving knife
malfunction.
If the counter knife pressure is too low :
・ The thread may not be trimmed.
・ Single yarn of the thread will remain after
thread trimming. The needle thread will
be caught in the thread trimmer to cause
the needle thread to be hitched when
the material is taken out from the sewing
machine.