SINGER W102 - Manual (Page 15)

REGULATING THREAD TENSION
NOTE : The upper tension is always released when the presser foot
is raised. Do not attempt to change or regulate upper tension until
presser foot is lowered all the way to the feed dog.
Fig. 9
To have a perfect stitch the threads must
be equally tightened from above and below
so that they join in the middle of the
material being sewn. Sheer material
requires a loose tension, while heavy
material requires more tension.
TO TIGHTEN the tension, turn the thread
tension regulator to the right.
TO LOOSEN the tension, turn the thread
tension regulator to the left.
Lower tension regulator
As all machines are
correctly adjusted before
leaving the factory and
readjusted before delivered to you, the lower tension
seldom requires changing; but if this becomes
necessary, tighten the screw in the tension spring
on the outside of the bobbin case for more tension,
or loosen the screw slightly for less tension.
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