How do I sew on a button?

The part people skip is the shank, and it is the part that decides whether the buttonhole closes properly. A button sewn flat against the fabric has nowhere for the buttonhole layer to sit, so the garment strains and gapes.

By hand. Mark the position. Bring the needle up through one hole and down through the next, over a matchstick, a thick needle or a toothpick laid across the top of the button. Repeat six to eight times. Remove the spacer, bring the thread up between the button and the fabric, and wind it tightly around the loose threads several times to form a shank. Take the thread through to the back and secure with two or three small stitches.

By machine. Drop the feed dogs or fit the cover plate. Fit a button sewing foot, which holds the button steady. Set a zigzag and — critically — turn the handwheel by hand first to check the needle drops cleanly into each hole. Adjust the zigzag width until it does. Sew six to eight stitches, then set the width to zero and sew a few stitches in one hole to lock. Lay a thin cord or needle across the button to create the shank space.

Thread. Doubled ordinary thread, or buttonhole twist for coats. Polyester rather than cotton.

Shank length. Match it to the thickness of the fabric the buttonhole is in — thick coating needs a long shank, a shirt needs almost none.

Reinforce underneath on soft fabric with a small backing button or a scrap of interfacing.