4-4) LOWER (BOBBIN) THREADING AND
TENSION ADJUSTMENT
1) Lower Threading
①
Use cotton yarn (#80-#120) for your lower
thread.
②
Threading the bobbin:
·
Insert the threaded bobbin into the bobbin
case with the thread coming out from the case
slot. Pull the thread through the thread guide.
Check if the bobbin is rotating ([Fig.4-9]).
·
Thread the lower thread holder and trim the
thread to 3-4cm before inserting the bobbin
and the case into the hook assembly. Long
tail can cause the thread to tangle during
stitching.
2) Lower Thread Tension Adjustment
Adjust the tension of the lower thread using the nut on the tension spring on the bobbin case. Turn the nut
clockwise to increase the tension and counterclockwise to decrease the tension.
[Fig.4-9]
Lower thread holder
bobbin
slot
screw
tension spring
thread guide
[CAUTION]
Direction of the Bobbin Rotation
Make sure that the bobbin rotates clockwise when you pull the thread holding the bobbin case in your left
hand, as shown in [Fig.4-9].
[CAUTION]
For adequate bobbin thread tension, hold a thread
from the bobbin and jiggle the bobbin case lightly up
and down as shown in [Fig.4-10]. The case should
drop and the tension should be 25-35g.
[Fig.4-10]
Bobbin case
Driver
