Mistakes & fixes

Thread that snaps repeatedly while sewing is usually old or low-quality thread, a burred needle eye, or tension set too tight for the thread weight. Use fresh quality thread, replace the needle, and ease the tension.

A tangled clump of thread on the fabric underside, jamming the feed, comes from unbalanced tension or starting a seam without holding the thread tails. Rethread fully, check tension, and hold tails taut when starting.

Thread fraying into fuzz or snapping into short pieces usually means it's catching on a burred needle eye or thread guide, or is old and brittle. Replace the needle, check guides for nicks, use fresh thread.

Stitches that pucker the fabric or feel stiff usually mean tension is set too high, pulling both threads too taut. Lower the top tension and check the bobbin isn't wound too firmly.

Loops of top-color thread on the fabric's wrong side signal top tension that's too loose, or a bobbin wound or threaded incorrectly. Tighten the top tension and rewind the bobbin evenly.

A raised ridge forming along a line of stitching on stretch fabric happens when tension is too tight or the stitch is too dense for the fabric's give. Loosen tension and use a walking foot with a stabilizer.