Kenmore 1350 - Adjusting Top Thread Tension; Adjusting Bobbin Thread Tension

Probably the most important control on your
machine is this one that regulates your top
thread tension.
There are many reasons for having to reset
your tension. The best tension for one fabric
may not be correct for another. The required
tension depends upon the stiffness of the
fabric, thickness of the fabric, numbers of
layers of fabric being sewn, as well as the
type of stitch you are making.
It is best to test the stitching on a scrap of the
fabric you are using before starting to make a
garment. Use the straight stitch function as
shown at the right.
When stitching is unsatisfactory in figures 2
and 3 above, adjust the upper thread tension.
LOWER THREAD TENSION REQUIRES
ADJUSTMENT LESS FREQUENTLY THAN
THE UPPER THREAD TENSION.
When stitch is satisfactory, as in Fig. 1 and
seam is badly puckered, the cause may be
tight tensions and both upper and lower may
have to be adjusted.
To test if the bobbin thread tension is correct,
suspend the bobbin case by the thread and
jerk it once. Correct bobbin tension will result
in the thread unwinding only one inch or two.
If too loose it will unwind continuously. If too
tight the thread will not unwind at all.
When adjusting the tension on the bobbin
case, make slight adjustments with a screw 
driver.
An ideal straight stitch will have
threads locked between the two
layers of fabric.
Upper thread too tight
Upper thread too loose
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