SINGER 319K - Manual (Page 40)

38
TO REGULATE BOBBIN THREAD TENSION
The tension on bobbin thread is regulated by
the larger screw nearest the center of the ten­
sion spring, as shown in Fig. 61.
When adjusting bobbin thread tension, a slight
turn of the screw is all that is needed to make
a fine adjustment, because the full range of
tension from zero to a maximum is made
within IM turns of tension regulating screw.
To increase tension, turn this screw gradually
over to the right.
To decrease tension, turn this screw gradually
over to the left.
Balanced Tensions