How do I sew stretchy fabric on an ordinary sewing machine?

You do not need an overlocker. What you need is a seam that can extend as far as the fabric does, a needle that pushes the knit loops aside rather than cutting them, and a way of stopping the fabric being stretched by the machine while you sew it.

What you'll need

• Ballpoint or stretch needles
• Polyester thread
• A walking foot (optional)
• Clips instead of pins (optional)

Step by step

1. Fit a ballpoint or stretch needle.A knit is made of interlocking loops. A sharp point cuts a loop, and a cut loop runs, which is why little holes appear along a seam a few wears later. A rounded point slips between the loops instead.
2. Use polyester thread, not cotton.Polyester has a little inherent stretch and much better recovery. Cotton thread is inelastic and snaps.
3. Choose a stitch that can extend.A narrow zigzag, roughly 0.5 to 1mm wide and 2.5mm long, is the general answer. Many machines also have a stretch or lightning stitch, which is stronger but slower to unpick. Straight stitch is only acceptable on a seam that will never be stretched, such as a shoulder seam that is stay-taped.
4. Reduce the presser foot pressure if you can.Heavy pressure stretches the fabric under the foot as it feeds, and the seam comes out wavy and permanently longer than the piece it joins. Not all machines have this adjustment.
5. Use a walking foot for anything slippery or heavy.Fleece, jersey with a high elastane content, and sweatshirting all shift badly. A walking foot drives both layers.
6. Stop pulling and stop pushing.Supporting the fabric level with the bed is fine. Any tension you apply is stretch that gets sewn in and stays there.
7. Stabilise the seams that must not stretch.Shoulders and necklines carry weight and should stay the length you cut them. Sew a strip of clear elastic or stay tape into those seams as you stitch.
8. Finish the edge only if it needs it.Most knits do not fray, so the raw edge can be left. If you want it tidier, trim close to the seam and run a second narrow zigzag along the edge.
9. Hem with a twin needle or a zigzag.A twin needle gives two parallel lines on the front and a zigzag underneath, which is what ready-to-wear uses and it stretches. A plain straight-stitched hem on jersey will pop.
10. Test the finished seam by stretching it.On a scrap, pull the seam hard across the stitching. If the thread breaks, the stitch has no give and the settings need changing before you touch the garment.

Tips

• Clips rather than pins on anything thick — pins distort a knit and are hard to remove as you sew.
• Cut knits with the greatest stretch running round the body, not up and down it.
• Let jersey relax flat for a few hours after cutting before you sew it; it will have stretched on the roll.

Common mistakes

• Straight stitching a stretch seam — There is nothing in a straight stitch that can extend. The thread takes the whole strain and snaps, usually somewhere that shows, and often in the middle of a wear rather than at the wash.
• Sewing jersey with a universal needle — It pierces the knit loops rather than parting them. The cut loops run later and produce a line of small holes along an apparently sound seam.

If it doesn't work

Questions people ask