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18.Adjusting the thread tension (Fig.16、17)
19.Adjusting the thread take-up spring (Fig.18、19)
In general, the thread tension s to be adjusted
in accordance with materials thread and others.
In practice, the thread tension is adjusted ac-
cording to the stitches resulted and has the normal
stitches.
The needle thread tension should be adjusted
with referance to the bobbin thread tension. when
adjusting the bobbin thread tension, turn bobbin
case tension spring screw (A) ( Fig.16 ) clockwise
for more tension or turn the screw counter clockwise
for less tension.
It is a common practice to check the bobbin
thread tension. In case of polyester thread 14 tex
(42s), hold the end of the thread and vibrate the
bobbin case up and down. If the bobbin case falls
down slowly (Fig.17), the proper tension is obtained.
The needle thread tension can be adjusted by chang-
ing tension of the thread take-up spring, tension of
tension disc, and the position of thread guide, all
these adjustments will be described as follows.
i
The normal sewing range of the thread take-up sprina is 5~8 mm. For sewing light weight materials (short
stitch), weaken the spring tension and widen the sewing range of spring, while for sewing heavy weight materials,
strengthen the spring tension and shorten the sewing range of spring.
1) Adjusting the thread take-up spring tension(Fig.18)
Loosen tension stud set screw (A), turn tension
stud (B) clockwise to make the spring get more
tension, or turn the tension stud counter clockwise
to make the spring get less tension . After adjustment,
Be sure to tight tension stud set screw (A).
The method of adjustment:
Loosen set screw (A) first, then to turn tension
stud (B) counter clockwise to reduce the tension of
thread take-up spring (C) to zero, and to turn tension
stud (B) clockwise until spring (C) just comes into
contact with the stopper on the thread take -up spring
regulator, then to further turn
tension stud (B)
clockwise
by
turn. After
adjustment,
tighten
tension stud set screw (A).
18
A
B
C
17
16
A
B
A