Length controls how far the feed dogs move between stitches; width controls how far the needle swings sideways. On a straight stitch, width does nothing. The practical settings are: 2.5 mm for construction, 3.5 mm for topstitch and thick fabric, 2 mm for fine fabric, 4 mm plus for basting. Width matters for zigzag, where a 3 mm width and 1 mm length gives a satin stitch and a 5 mm width with 2.5 mm length gives a stretch-tolerant seam finish.
Questions people actually ask
What stitch length should I use?
About 2.5 mm for general construction on medium woven fabric. Go to 3 to 3.5 mm for topstitching and for thick fabric, and down to 2 mm for fine fabric and curves. Basting is 4 mm or longer so it pulls out easily.
Why does a longer stitch help on thick fabric?
Because each stitch has more fabric to bite into and the feed dogs have to move a thicker layer. A short stitch on denim perforates the fabric almost continuously, which weakens the seam and jams the feed.
Last reviewed 2026-08-11