Gusset

A gusset is a small piece of fabric, usually a diamond, triangle or narrow strip, set into a seam where several pieces meet at a point. Its job is to add room for movement exactly where a garment would otherwise pull or tear. The classic example is the underarm of a close-fitting kimono sleeve: without a gusset, lifting your arm pulls the whole side of the garment up with it and puts strain on the underarm point. With a gusset, the extra fabric opens out as the arm lifts.

Where gussets are used

• Underarms of kimono and dolman sleeves, where the sleeve is cut in one with the bodice. A diamond gusset is set into the underarm seam. See Sleeve.
• Traditional shirts and chemises. Garments built from rectangles of fabric used square underarm gussets, and sometimes small gussets at the neck and side vents, to fit a body without curved pattern pieces.
• Crotches of trousers, leggings, tights and underwear, where a diamond or strip of fabric adds room and spreads the strain.
• Bags and pockets, where a strip of fabric adds depth.

Why they work

Where seams meet at a sharp point, such as an underarm, all the strain of movement concentrates on that point. A gusset spreads it across a larger area and adds length exactly where the body needs it, without making the rest of the garment looser.

Sewing a gusset

Gussets have a reputation for being fiddly, because the points have to meet exactly. To make it easier:

1. Reinforce the point on the garment where the gusset goes: staystitch around it with short stitches, or fuse a small square of lightweight interfacing behind it.
2. Mark precisely. Mark the stitching lines and the exact points on both the gusset and the garment.
3. Slash the garment to the point, cutting exactly to the reinforcement stitching but not through it.
4. Sew one side at a time, from point to point, with the garment side up. At each point, stop with the needle down, lift the presser foot, pivot, and spread the slash so the next side lies flat.
5. Use a shorter stitch for an inch or so either side of each point, for strength.
6. Press the seam allowances away from the gusset, and topstitch around it if the design allows, for extra strength.

On knit garments, gussets are easier, because the fabric gives a little at the points.

Gusset or a different sleeve?

If you love the look of a kimono sleeve but don't want to set a gusset, choose a looser kimono or dolman design with a deeper underarm curve, which allows movement without one, or switch to a raglan sleeve.