Adjusting The Thread Tension - JUKI PS-800-12080 Instruction Manual

4-5. Adjusting the thread tension

❶
❷
❺
A
B
❸
❹
Fig. A
Fig. B
Fig. C
– 16 –
(1) Adjusting the needle thread tension
Thread tension controller No. 1 ❶
When the tension disk of thread tension controller
No. 2 ❸ is loosened, such a small tension as to
control the thread trimmer has to remain. The re-
maining tension is produced by tension controller
❶ . It is possible to determine the length of thread
trailing from the needle after automatic thread
trimming by adjusting nut ❷ of the thread tension
controller. The length of thread trailing from the
needle is reduced by turning nut ❷ clockwise (+).
It is increased by turning nut ❷ counterclockwise
(-).
Thread tension controller No. 2 ❸
The tension (applied to the thread coming from
the needle) controlled with thread tension con-
troller No. 2 ❸ should be set as low as possible
so that the needle thread and bobbin thread are
interlaced together at the center of material thick-
ness (Fig. A). If the thread tension is excessively
high when sewing a light-weight material, the ma-
terial may become wrinkled or thread may break.
The tension applied to the thread coming from the
needle is increased by turning nut ❹ clockwise
(+).
It is decreased by turning nut ❹ counterclockwise
(-).
Fig. A: Threads are interlaced together accurately at
the center of material thickness.
Fig. B: Needle thread tension is too low or bobbin
thread tension is too high.
Fig. C: Needle thread tension is too high or bobbin
thread tension is too low.
(2) Adjusting the bobbin thread tension
1) Turn tension adjusting screw ❺ clockwise (in
direction C) to increase or counterclockwise (in
direction D) to reduce the bobbin thread tension.
Recommended value: Approximately 25 g
The bobbin case will come down slowly by its
dead weight by holding it as illustrated in the fig-
ure.