-9-
20.Adjusting the thread of needle thread & bobbin thread (Fig.20、21、22)
2) Adjusting the sewing range of t hread take-up
spring (Fig.19)
Loosen set screw (B), turn tension complete (C)
clockwise to increase the sewing range or turn
tension complete (C) counter clockwise to decrease
the sewing range.
Before delivery, the thread take-up spring is
properly adjusted, Readjustment is needed only in
the case of sewing special materials or with special
thread.
The position of the thread guide affects sewing
quality, so it must be adjusted according to the ma-
terials to be sewn.
Fig.20 shows the various type of stitch forms.
Normal stitch form should be as shoun in Fig.
20(a). When adnormal stitches occur with pucke ring
or thread breakage, the tension of needle thread and
bobbin thread must be adjusted accoringly.
(a) The needle thread tension is too strong or
the bobbin thread tension is too weak, turn the ten-
sion regulating thumb nut counter clockwise to make
the needle thread get less tension or tighten the
bobbin case tension regulating screw with small
plastic screw driver to make the bobbin thread get
more tension (Fig.21).
19
A
B
C
D
5-8mm
21
20
a
b
c
d
e
Thread guide
position
Leftward
Center
Rightward
Material
Heavy
Medium
Light
