Staystitching

Staystitching is a line of ordinary machine stitching sewn through a single layer of fabric, just inside the seam allowance, along an edge that's likely to stretch. It's done soon after cutting, before the piece is handled much. The stitching acts like a fence: it stops the threads at the edge pulling apart and the curve growing as you pin, fit and sew.

It's a small, quick step that patterns often mention in passing. Skipping it is one of the most common reasons for gaping necklines, wavy armholes and collars that don't fit their neckline.

Where to staystitch

Any edge that's curved or cut on the bias, which covers:

• Necklines, especially before a collar or facing is attached.
• Armholes on sleeveless garments.
• Curved waistlines on skirts and trousers.
• Shoulder seams on loosely woven fabrics.
• Points and corners that will be clipped, such as the V of a V-neck or the corners of a square neckline. These can be reinforced with shorter stitches.
• The concave edge of a princess seam. See Princess Seam.

Straight edges on the grain usually don't need it.

How to staystitch

1. Do it as soon as the pieces are cut, before pinning or fitting.
2. Stitch about 1/8" (3 mm) inside the seamline, within the seam allowance. On a 5/8" (1.5 cm) allowance, that's about 1/2" (1.3 cm) from the edge, so the staystitching won't show after the seam is sewn.
3. Use a normal stitch length, around 2-2.5 mm, through a single layer.
4. Stitch in the direction of the grain, which usually means from the higher, wider point toward the narrower one. On a neckline, stitch from each shoulder toward the centre, in two separate passes, rather than all the way round in one direction. That way you don't push the grain to one side.
5. Don't pull or push the fabric. Let the machine feed it.

Staystitching and clipping

Curves that need clipping before they're sewn to another piece, such as a neckline before a collar is attached, are clipped to the staystitching but not through it. The stitching tells you exactly how far to clip, and stops the clips going too far.

Related stitches

• Stay tape: a narrow tape or a strip of lightweight fusible interfacing sewn or fused along an edge that must not stretch at all, such as a knit shoulder seam, a zip opening or a bias waistline. It's stronger than staystitching. See Zipper Insertion.
• Easestitching: similar long stitches drawn up slightly to ease a longer edge into a shorter one. See Ease.