Lower Thread Tension; Upper Thread Tension; Thread Take-Up Spring Height; Thread Take-Up Spring Tension - Brother BAS-341F Instruction Manual

5. CORRECT USE

5-6-2. Lower thread tension

Weaker
(1)
Set the lower thread tension to as weak a tension as
possible and so that the bobbin case drops by its own
weight when the end of the thread is held. Turn the
adjusting screw (1) to adjust the tension.
Note
If the lower thread tension is too weak, it may not be
possible to cut the lower thread properly during thread
trimming.

5-6-4. Thread take-up spring height

Loosen screw (4) and turn the entire thread take-up unit to
adjust so that the height of the thread take-up spring is 8 -
10 mm
13
Stronger
0112S
Lower
Higher
1938S

5-6-3. Upper thread tension

Turn the tension nut (2) (main tension) to adjust the tension
as appropriate for the material being sewn.
Furthermore, turn the thread nut (3) (sub-tension) to adjust
the remaining length of upper thread to 35 - 40 mm.

5-6-5. Thread take-up spring tension

Adjust the thread take-up spring tension by turning the
tension stud (5) with a screwdriver.
BAS-341F, 342F
Stronger
Weaker
Stronger
Weaker
1937S
Stronger
Weaker
1939S