JUKI LK-1900B Series Engineer's Manual page 43

Adjustment procedures
1. If the thread on Side B cannot be cut, grind Side C. If the thread
on Side C cannot be cut, grind Side B.
(Caution) When grinding the side, make the angle more acuter
than 90 degrees.
Adjustment procedures
1. Turn off the power supply and look for any close contact between
the AT solenoid ❶ and the thrust collar ❷ .
2. Loosen the three setscrews ❸ and remove the thread tension
cap ❹ .
3. Hold the tension releasing pin adjust collar ❺ not to let it rotate,
and loosen the nut ❻ .
4. Turn the tension releasing pin adjust collar ❺ and adjust the gap
between the thread tension discs ❼ . (Adjustment of thread ten-
sion disc floating)
5. Hold the tension releasing pin adjust collar ❺ and tighten the nut
❻ . Mount the thread tension cap ❹ by means of the setscrew ❸ .
6. Turn on the power supply and set up the thread tension. Confirm
that the thread tension discs ❼ are closed.
Secure an acute angle.
– 29 –
Results of Improper adjustment
When less than 0.2 mm:
o
Thread on Side C cannot be
cut.
When more than 0.2 mm:
o
Thread on Side B cannot be
cut.
Results of Improper adjustment
If the amount of disc floating
o
is too less, the residual thread
length can be changed or short-
ened when the thread is thick.
If the amount of disc floating
o
is too much, the tension discs
cannot close completely and
normal thread tension may fail to
be chosen. This can be a cause
of imperfect sewing.