SunStar KM-640BL, User Manual

17

6) Winding and adjusting lower thread

Winding lower thread

a) Pass the thread thru the hole

①

from the rear to the

frontal side of the tension adjusting dish

②

.

b) Bring the thread to the bobbin

③

and wind it

clockwise 5 to 6 times from the bottom.

c) Push the lever

④

so that the pulley

⑤

touches the V-

belt and run the machine.

d) The pulley

⑤

automatically is separated from the V-

belt when the lower thread is winded in the bobbin.

e) The adequate amount of the pulled-out lower thread

is about 80%. (Refer to Figure 24)

[Figure 24]

Adjustment of winding lower thread

a) In case that the lower thread is winded irregular, loosen the bolt

⑥

and adjust by moving it sideways, and tight it again.

b) The amount of winded lower thread becomes larger when you turn adjusting screw

⑦

clockwise, and it becomes

smaller in case of turning it counterclockwise.

c) The tension of lower thread that winded in the bobbin can be adjusted by turning the nut

⑧

: it increases with

clockwise turning and it decreases when you turn counterclockwise.

[Figure 25]

7) Inserting and removing lower thread and adjusting tension

Insert the bobbin into the bobbin case.  Later, insert the thread into the thread groove

③

and place it under the spring

④

of

thread adjusting plate.  The tension of the lower thread becomes larger when you turn clockwise the tension adjustment

screw

⑤

and becomes smaller when you turn in counterclockwise. When hold the end of thread, make sure that the

bobbin case

⑥

should drop by gravity in order to adjust the lower thread tension.

Inserting and removing the bobbin case

Insert into the hook by grabbing the bobbin case handle

①

.  Pull out the handle

①

when you remove the bobbin. (The

bobbin

②

removes itself when you release the handle.)

Weaker

Stronger

Caution

▶

Turn off the power when adjusting the lower thread tension.  

▶

If the operator mistakenly steps down on the pedal while switched on, the machine will start
automatically and can cause physical injuries.

▶

When using the clutch motor, be aware that the motor will continue to rotate for a while after
the power is switched off.  Start to work only after the motor has come to a complete stop.