Brother KE-434C Instruction Manual page 36

7. CORRECT USE
7-6-2. Guide to maximum sewing speed
Use
8 layers of denim
12 layers of denim
Ordinary materials
Note:
The thread may break due to heat under some sewing conditions.
If this happens, reduce the sewing speed, or use the liquid cooling tank (option).
7-6-3. Lower thread tension
Weaker Stronger
7-6-4. Upper thread tension
30
Max. sewing speed(rpm)
Standard hook
2,500
2,300
2,500
2536Q
Stronger
Weaker
Stronger
Weaker
2537Q
KE-434C,435C
Large hook
2,500
2,500
Adjust the thread tension to the weakest possible tension by
turning the thread tension nut (1) until the bobbin case will not
drop by its own weight while the thread end coming out of the
bobbin case is held.
Turn the tension nut (1) (main tension) to adjust the tension as
appropriate for the material being sewn.
Furthermore, turn the thread nut (2) (sub-tension) to adjust the
remaining length of upper thread to 35 - 40 mm, when the thread
take-up lever is not used.