2) Bobbin Case Insertion/Removal; 3) Tension Adjustment - SunStar SPS/E-BS1201 Series User Manual

5.3.2) Bobbin Case Insertion/Removal

Open the hook cover and push the bobbin into the hook
by holding the bobbin case handle until you hear some
sound.
If the bobbin case and the hook are not accurately assembled, thread might be entangled or the
bobbin case might be ejected during machine operation. Make sure that the bobbin case is
completely inserted into the hook before operating the machine.
Caution

5.3.3) Tension Adjustment

1) Adjustment of Upper Thread Tension
Turn the tension adjusting nuts of the main and sub
thread adjusting devices clockwise, and the tension
of the upper thread will grow strong. Otherwise, the
tension of the upper thread will grow weak.
Adjust the thread tension in accordance with the
sewing conditions including sewing materials,
thread, and number of stitches.
2) Adjustment of Thread Take-up Lever Spring Tension
Adjust the tension of the thread take-up lever spring
by using the bolt on the main thread adjusting device
axis. If the bolt is turned clockwise, the thread take-
up spring tension will be strengthened. Otherwise,
the tension will be weaker. (The standard movement
volume is 6-8mm, and the standard tension is 30-
50g.)
3) Adjustment of Lower Thread Tension
If the bobbin case tension adjusting screw is turned
clockwise, the lower thread s tension will grow
strong. If the bobbin case tension adjusting screw is
turned counter-clockwise, the lower thread s tension
will grow weaker.
Main Thread Adjusting Device
Weaker
Stronger
Tension Adjusting
Screw
Sub Thread
Adjusting Device
21