33
[ Fig. 44 ]
F. Replacing fixed knife
ⓐ
As in the Figure 44, unfasten fixed knife clamp screw on
fixed knife base to disassemble it. To assemble, follow
the reverse order of disassembling.
②
①
[ Fig. 46 ]
7) Adjusting the Main Thread Control
Device
ⓐ
If the tension control nuts
①
of thread control device is
turned clockwise, the tension of upper thread will increase.
If turned counter-clockwise, the tension will decrease.
Because the tension control is affected by sewing
conditions such as sewing material, thread and stitch, adjust
tension according to conditions.
ⓑ
To adjust tension of thread take-up spring, insert drive in the
groove of thread tension control device
②
. Then turning the
drive clockwise will increase tension of thread take-up
spring and turning counter- clockwise decrease the tension.
ⓑ
If thread is not trimmed or thread is not cut clean, check
cutting edge of fixed knife.
If the edge of fixed knife is worn, as in the figure 45,
hone the fixed knife on a oilstone.
[ Fig. 45 ]
Fixed knife
Oilstone
Thread Take-Up
Spring
①
②
