Thread Tension; Adjusting The Thread Tension - Brother T-8420B Instruction Manual

7. THREAD TENSION

7. THREAD TENSION

7- 1. Adjusting the thread tension

Good even stitches
<Latch type>
Becomes weaker
<Bobbin case type>
2923M
Becomes stronger
Becomes weaker
25
Upper thread
Lower thread
0572M
Upper thread tension too weak or
lower thread tension too strong
0573M
Upper thread tension too strong
or lower thread tension too weak
0574M
Becomes stronger
Becomes stronger
Becomes weaker
Becomes weaker
Becomes stronger
T-8420B, 8450B, 8720B, 8750B
<Lower thread tension>
2990M
Turn off the power switch before adjusting the
lower thread tension. The motor will keep turning
even after the power is switched off as a result of
the motor's inertia. Wait until the motor stops fully
before starting work.
The machine may operate if the treadle is
depressed by mistake, which could result in injury.
Turn the adjusting screw (1) to adjust.
<Upper thread tension>
After the lower thread tension has been adjusted, adjust the
upper thread tension so that a good, even stitch is obtained.
1. Lower the presser foot.
2. Adjust by turning the tension nut (2).
2924M
Increase the upper thread tension.
Decrease the lower thread tension.
Decrease the upper thread tension.
Increase the lower thread tension.
CAUTION