SINGER 2118 - Manual (Page 16)

Adjusting Needle Thread Tension
Bobbin thread tension is preset by factory but
the top thread tension can be adjusted to suit
different sewing situations.
* For most stitching, setting the tension from
3 to 5 should produce satisfactory results.
^
If stitching appears loose or small loops are
visible on the bottom of the seam, the tension
should be increased.
^
Turn dial upwards towards the higher numbers
until stitching is acceptable.
^
If stitching appears tight and fabric puckers,
the tension should be decreased.
^
Turn dial downwards towards the lower numbers
until stitching is acceptable.
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