−
16
−
Properly installing the thread guide for knife
Install the thread guide for knife so that the needle enters just in the center of the window (hole).
3-8 Rising amount of the thread tension disk No. 2
1) Observing the rising amount of the thread tension disk No. 2
Lift the presser foot at the position where the thread take-up lever comes slightly to this side of its upper dead
point. Then, check that the rising amount of the thread tension disk No. 2 is 0.5 to 1mm when thread take-up
picker (Fig. 12 (1)) is pressed to the right.
2) Adjusting the rising amount of the thread tension
disk No. 2
①
To increase the rising amount, loosen screw
(Fig. 21 (1)) and move thread release wire (2)
to the right.
②
To decrease the rising amount, loosen screw
(1) and move thread release wire (2) to the
left. After performing adjustment, securely
tighten screw (1).
3-9 Sharpening the knife blade
The shape of blade top of the counter knife affects most the sharpness of the knife.
In many cases, the sharpness is improved by sharpening the blade of the counter knife only.
It is important that the blade face of the counter knife comes in contact with the blade section of the moving knife.
○
The sharpness is improved by sharpening face A in Fig. 22 only. (Pay attention to the angle shown in Fig. 22.)
(1)
(2)
X
D
C
Take corner and polish well.
Fig. 21
○
The sharpness is deteriorated when the top end of face B has been worn out and got round. Carefully sharpen
the blade without changing the angle.
Sharpen this face. (Face A)
Blade top (Face B)
Counter knife
Fig. 22
Moving knife
Counter knife
C and D sections of moving knife should
simultaneously come in contact with counter knife.
Fig. 23
