Pfaff 433 - Regulating the Thread Tensions

9. Regulating the Thread Tensions
To obtain o perfect seam, observe the following hints:
The needle and bobbin threads should be locked in the center of the material
as shown in Fig. 8.
Turn tension nut M (Photo 6} clockwise for a tijhter upper tension, and
counter-clockwise for a looser tension.
The lower tension is regulated by means of tens
the small screw driver and turn this screw eithe
tension, or counter-clockwise for a weaker tensia
on screw z (Fig. 9). Take
' clockwise for a tighter
n.
The tension should be regulated in accordance with the material to be sewn
and should be such that the stitches will be tightly set, yet without causing
seam pucker, and that they will lie in a straight ine on the surface of the
goods.
The grade of thread used plays an important part in obtaining a perfect
seam on any material.
Sheer fabrics require a thin and soft thread. Stiff and resistant threads are
unsuitable for almost any fabric because of their low resilience.
In regulating the thread tensions you have to have a little experience before
you can lell which tension neecis adjustment. In
tension may be too tight or the lower tension too loose.
Fig. 10 either the upper
10
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