Reliable MSK-8420B instruction manual Needle thread tension Increase Reduce

b. If the needle thread is too loose and the bobbin thread is too tight, then shows as Fig. 20C, And turn the thread tension screw clockwise to increase the needle thread tension; or turn loose the bobbin lace screw to reduce the bobbin thread tension. (See Fig. 21, 22)

For special sewing with special thread, the ten- sion needed can be obtained by adjusting the power and stroke of the thread take-up spring.

5.2 Adjusting the pressure of presser foot (Fig.23)

22

needle thread tension

increase

reduce

The pressure of the presser foot should be adjust- ed according to the thickness of the sewing materials. If stitch on heavy duty material, the pressure should be increased and turn the pressure adjusting screw on the back of the arm clockwise if reduce the pressure, turn it counter-clockwise.

increase

23

reduce

5.3 Use and adjustment of the safety clutch device

The function of the safety clutch device is to prevent the hook and teeth-belt from destroy when the needle thread is drawn into the hook for adnormal load during the operation.

5.3.1The function of the safety clutch device(Fig.24)

a.When the safety clutch device is functioning, the teeth-belt will remove the load and the rock shaft will stop rotating, only the upper shaft rotates, and the machine stops work.

b.Clean off the needle thread which is drawn in the hook.

c.Turn the shaft of the teeth-belt with hand to check if the rock shaft can turn smoothly, then reset the safety clutch device.

5.3.2Resetting the safety clutch device.

a.While press down the button in the bed surface with left hand, turn the balance wheel slowly with right hand in the direction shown in Fig. 25.

pressure adjusting screw

24

safety clutch device teeth - belt pulley

shaft

25

balance wheel

button

-8-