A coverstitch machine makes the parallel rows of stitching you see on the hem of a shop-bought T-shirt, with a looped chain covering the raw edge on the underside. It stretches, which is the whole point.
How it differs from an overlocker. An overlocker trims and encloses an edge to build a seam. A coverstitch does neither — it does not cut, and it does not make an edge seam. It hems and it topstitches, with give. Some machines do both jobs, but converting between them takes time and re-threading, which is why people who use both regularly end up with two machines.
What you gain. Knit hems that stretch instead of popping their stitches, decorative chain stitching, and flatlocking. It is the single most visible difference between a home-made and a shop-bought jersey garment.
The cheaper answer that works. A twin needle in an ordinary sewing machine gives two parallel rows on top with the bobbin thread zigzagging between them underneath. It stretches reasonably well, it looks close, and it costs the price of a needle. For most people who sew jersey occasionally, this is enough — and it is worth exhausting before spending on a machine.
When to buy one. When you sew knit garments regularly and hemming is the step you are consistently unhappy with. It is a third machine, after a sewing machine and an overlocker, not before either.
What to expect. Threading is fiddly and order-dependent. Tension is sensitive. Skipped stitches are the standard complaint and are usually a needle or a stabiliser issue. Test on scraps of the actual fabric every single time.
Questions people actually ask
Can a coverstitch replace my overlocker?
No. It does not trim or enclose a raw edge, so it cannot construct a knit seam the way an overlocker does. They do different jobs.
Why does my coverstitch skip stitches on jersey?
Usually a blunt or wrong needle, or unsupported stretchy fabric. Fit fresh ballpoint needles of the correct system and stabilise the hem with fusible tape.
Last reviewed 2026-08-11