A twin needle is two needles on one shank, so a single pass produces two parallel rows of stitching. Its main use at home is hemming knits.
Why it works on jersey. On top you get two straight rows. Underneath, the single bobbin thread zigzags between them, which gives the seam enough give to survive being stretched. That is the coverstitch look without a coverstitch machine.
Sizes. Marked as two numbers, for example 4.0/80 — 4 mm between the needles, size 80. Narrow spacings suit fine fabric; 4 mm and 6 mm are the usual hem widths.
Before you start, three checks.
Set the stitch width manually. A 4 mm twin needle in a machine set to a 5 mm zigzag will strike the needle plate on the first stitch and break both needles. Set the width to zero for straight stitching and confirm by turning the handwheel by hand.
You need two spools of top thread and somewhere to put them. Most machines have a second spool pin; if not, wind a bobbin and use it as a second spool.
If the hem tunnels — a ridge between the two rows — reduce top tension, lengthen the stitch slightly, and back the hem with a strip of wash-away stabiliser.
Questions people actually ask
Is a twin needle as good as a coverstitch?
Close on the top surface, less durable and less elastic underneath, and a fraction of the cost. For occasional hems it is the sensible answer.
Can I use a twin needle on any machine?
Any machine that does a zigzag has a needle hole wide enough. Machines with straight-stitch-only plates do not.
Last reviewed 2026-08-11