Kenmore 1218 Instructions Manual page 29

ADJUSTING YOUR SEWING MACHINE FOR GOOD STITCHES
When your sewing machine does not sew a properly locked stitch, check the following:
1. Insert a new needle of the correct size for the thread and fabric you are using.
Consult chart on page 7 for needle size.
2. The upper and bobbin thread should be the same thread.
3. Check threading carefully. See page 10-11.
4. Check the thread tension balance. Use mercerized thread and a correct size needle for the fabric you are
using. Do not try test with synthetic thread as it will not break. Begin with a full bobbin, properly threaded
into the case. Set stitch length at about 12 stitches per inch. Fold a 6 inch square of your fabric in half
diagonally, forming a triangle. Make a line of stitching _" from fold.
a. If seam is puckered -- both tensions are too tight.
b. If bottom thread is looped -- tighten upper thread tension, and repeat test.
c. If top thread lays in top of fabric-- loosen upper thread tension, and repeat test.
Grasp the stitching and pull evenly and firmly until one or both threads break.
a. If both threads break -- tensions are balanced.
b. If neither thread break- both tensions are too loose.
c. If upper thread breaks-- loosen upper tension.
d. if lower thread breaks- tighten upper tension.
Both threads do not have to break at the same place, but they should break on the same snap.
bobbin tensions may also be reset by this procedure. Start with a loose bobbin thread tension. Tighten the
spring screw gradually until bobbin case and full bobbin can be gently lifted from your hand by the end of the
bobbin thread.
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