Adjusting The Treadle Operation - Brother T-8421D Instruction Manual

5
With the machine head tilted back, depress the
treadle (1) and check that the sewing machine
does not operate.
NOTE
If the sewing machine operates when the treadle (1) is
depressed while the machine head is tilted back, the
safety switch is probably faulty. Contact the place of
purchase.
Related Information
• Adjusting the safety switch position on page 73

Adjusting the treadle operation

Adjusting the depression force
1
If the machine starts running at low speed when
your foot is simply resting on the treadle, or if the
treadle pressure is felt to be too weak, adjust the
position at which the treadle spring (1) is hooked
onto the treadle lever (2).
a is the weakest position, and it becomes gradually
stronger at b, c and d respectively.
Adjusting the reverse depression force
2
Loosen the nut (3) and turn the bolt (4).
When the bolt (4) is tightened, the treadle
operation becomes heavier, and when it is
loosened, the operation becomes lighter.
3
Tighten the nut (3).
Adjusting the treadle stroke
4
Remove the nut (5), and then move the
connecting rod joint (6) from the position in figure
A to the position in figure B.
The treadle stroke will then be increased by
approximately 27 %. At this time, the treadle
forward and backward depression sensitivity will
change, so readjust if necessary.
16