5-5. Thread tension; 5. Correct operation- Page 19

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BAS-761

5-5. Thread tension

w

q

r

e

Stitches when upper
thread tension is too low

Stitches when upper
thread tension is too high

Correct stitches

1.

When the thread take-up lever is in the highest position after thread trimming, adjust the upper thread beyond the
needle eye so as it is 30 to 40 mm long, by turning tension nut 

q

. (30 - 70 g is standard).

2.

Adjust the lower thread tension by turning tension regulating screw 

w

. (40 - 60 g is standard.)

3.

Adjust the upper thread tension by turning tension nut 

e

 and 

r

 after lowering the presser foot.

Note:

Then adjust the tension 30 - 40 g by turning tension nut 

r

.

Main adjust is performed by using tension nut 

e

.

  x2.4 rotary hook  150 - 200 g is standard.
  x1.7 rotary hook  200 - 220 g is standard.

■

 Thread take-up spring

1.

The standard height of the thread take-up spring 

q

 is when the stroke is 5 to 8 mm.In addition, the standard tension

in the thread take-up spring is 30 g to 60 g (x1.7 rotary hook 40 - 80g).
(The tension in the thread take-up spring when it is pulling the upper thread straight to the side at the point where
the spring starts to move.)

2.

To adjust the thread take-up spring height, loosen set-screw 

w

 and turn the whole unit of the tension regulator

assembly.

3.

To adjust the thread take-up spring force, insert a screwdriver tip into the groove of tension stud 

e

 and turn it as

much as is appropriate.

Low

High

w

e

q

q

30 - 60g

5 - 8mm

5. Correct operation

■

 x2.4 rotary hook

■

 x1.7 rotary hook

w

Low

High

e

■

 x2.4 rotary hook

■

 x1.7 rotary hook

(

)

■

 x2.4 rotary hook

■

 x1.7 rotary hook

e

40 - 80g