7-3
7-1-4) Adjusting Tension on Lower Thread Holder
①
Unscrew the movable blade crank. Cut the lower thread with the movable blade and check the cross-section of
the thread.
②
If the lower thread tension is too weak or too tight, use the tension control spanner (included in the SWF basic
kit) to unscrew the nut on the lower thread holder. Adjust the tension with the L-wrench.
③
Use the spanner to fasten back the nut.
7-2) ADJUSTING THE TRIMMER RETURN SPRING
1) Function
The trimmer return spring detects if the movable blade returns to the correct position after trimming. If the
machine operates without the blade returned to its correct position, the needle and the blade may be damaged. The
trimmer return spring detects and stops the machine if the blade has not returned.
2) Adjustment
①
Adjust so that the sensor spring is around 2mm off the center of the sensor when the movable blade is in its
correct position ([Fig.7-6]).
②
Adjust so that the sensor spring and the sensor are around 1mm apart.
③
Center of the sensor spring should align with the center of the sensor.
[Fig.7-6]
Trimming
shaft
Return
spring unit
Sensor
1mm
2mm
Sensor spring
By holding the thread coming from the bobbin case after trimming, the lower thread holder forms starting
stitches after trimming.
[CAUTION]
Clean the thread debris around the lower thread holder on a regular basis.
[Fig.7-5]
Tension adjusting spanner
for lower thread holder
Fixed blade screw
Fixed blade
sensor bolt
