A coverstitch makes the parallel-line hem you see at the bottom of every t-shirt: two or three needles on top, a looper underneath laying thread across the raw edge, and a finish that stretches with the fabric instead of snapping. It's a different machine from an overlock (which trims and encloses the edge) and from a lockstitch (which makes one straight seam with no stretch). If you're producing knits in any volume, this is the machine you're missing.
Still deciding between an overlock and a coverstitch? Start with our comparison of overlock vs coverstitch machines — this guide assumes you've landed on coverstitch and helps you pick which one.
First, the vocabulary
The stitch classes on the spec sheet
Every listing you'll read uses these numbers, and knowing them makes the rest of the decision obvious:
- 406 — 2 needles + 1 looper. Two straight lines on top, looper thread covering underneath. The standard t-shirt hem.
- 407 — 3 needles + 1 looper. Same thing with three lines.
- 602 — 2 needles + bottom looper + a top cover thread. Covered on both faces.
- 605 — 3 needles + bottom looper + top cover thread. This is what a listing means when it says "3 needle, 5 thread". Maximum coverage and maximum stretch, and the finish you see on quality activewear.
Question 1
Flatbed, cylinder bed, or small cylinder?
Flatbed: what you picture when you think "sewing machine table." Best for flat garments — tees hemmed before they're sewn closed, neckline bindings on lay-flat panels, decorative seams, flat-seam construction. The most common starter coverstitch, and the cheapest way in.
Cylinder bed: the work surface is a slim arm, roughly 60–90 mm across, and the fabric rotates around it. Required for finishing a hem after the garment is closed into a tube: hems on assembled tees, joggers, sportswear. If you finish garments after assembly, you need cylinder bed and nothing else will do.
Small cylinder: a narrower arm again, for the tight tubes — sleeve cuffs, collars, kids' garments. If sleeve cuffs are a daily operation, a standard cylinder will fight you and a small cylinder won't.
Question 2
2 or 3 needles — and at what gauge?
2 needles (406/602): two parallel lines on top. The standard look for most t-shirt hems and athletic apparel.
3 needles (407/605): three parallel lines, wider coverage and more elasticity. Worth it where the seam has to survive real stretch — waistbands, leggings, swimwear — and where you want the heavier hem look.
The gauge is the part nobody asks about. The number in the model name is the needle spacing: a ×364 machine is 3 needles across 6.4 mm (1/4"), a 356 is 3 needles across 5.6 mm. That spacing is fixed by the gauge set — needle plate, presser foot and looper — not by the needles.
So the usual advice, "start with 3 needles, you can always remove one," is only half true on an industrial machine. You can pull the middle needle and sew with the outer two, which gives you the wide 2-needle look. You cannot make the spacing narrower, and you can't go from 6.4 mm to 5.6 mm without changing the gauge set. Decide the gauge with the garment in front of you — and take the unused needle out rather than leaving it in.
The spec that isn't in anybody's three questions: differential feed
Two feed dogs, one behind the other, running at different speeds. Set the front one faster and it eases fabric in, which stops a stretchy jersey hem coming out wavy. Set it slower and it stretches the fabric as it feeds, for a lettuce edge or to pull in a slack panel.
On knits this is the control that separates a hem you'd sell from a hem you'd re-cut, and it's the first thing to set on a new fabric — before you touch the tensions. Every industrial coverstitch worth buying has it; what varies is the range and how easy it is to change on the fly. If you sew light single jersey, rib and spandex blends in the same day, ask about the range before you buy.
Question 3
How much of the cycle should the machine do?
The automation is what turns a coverstitch from a manual-cycle machine into a production machine. Skip it in a low-volume shop; include it if the machine runs cycles all shift, because it comes back in operator time.
- Automatic thread trimmer (UT). Cuts the chain at the end of every seam, so nobody is reaching for scissors a thousand times a day.
- Auto presser foot lift. Raises the foot for the operator between pieces.
- Knife / edge trimmer and suction. Trims and clears the chain and the offcut — worth it on high-volume hemming lines.
- Puller. A driven roller behind the foot that keeps long hems feeding evenly. Common on binding and waistband work.
- Binder (folder). The attachment that folds the tape and feeds it into the seam — this is what turns a coverstitch into a machine for attaching neck binding. Some models ship set up for it from the factory, which is a different machine from one you retrofit later.
What we'd buy, by how you answered
- Flatbed, small shop: JACK W4-D, SPEEDWAY SW 562/01CB, SIRUBA F007K-W122-356/FHA or JUKI MF-7523U11.
- Flatbed, production: JACK W4S UT 01GB or SPEEDWAY SW 562/01 CB UTE — same bed, with the trimmer and auto foot lift.
- Cylinder bed: SPEEDWAY SW 662-01/CB UTE, JACK K5E-UT, SIRUBA C007KP or KANSAI NR-9803GA.
- Small cylinder (cuffs and collars): JACK JK-8670G-01CBx364/UT.
- Binding from the factory: JUKI MF-7523C11, SIRUBA F007K-W222-356/FQ or SINGER 522D-356-03TB.
If you do tube-finished knits at volume: the JACK K7-UT is what we'd buy
An AI-smart cylinder-bed coverstitch with an automatic thread trimmer — its stitch optimisation adjusts as fabric weight and tension vary through a run, and it lands on the "production" side of every question above. Ships complete with table, stand, needle set and looper threader. If you also need the knife and suction, look at the JACK K6-A-UT. Current pricing is on the product page.
One thing to order with the machine, whichever you pick: coverstitch machines run the UY128GAS needle system, with a ball point (FFG or RG) for knits. Not DBx1, not DPx5.
Talk to a specialist
Tell us whether you sew garments closed first or hem flat, which fabrics you run in a normal week, and your daily volume. We'll point at the bed style, the gauge and the level of automation that fits — and tell you when the cheaper machine is the right answer.