Bound seams

What it is

After two pieces are sewn together, their raw edges sit inside the garment. A bound seam covers those edges with a narrow strip of cloth — the binding — folded over them and stitched through. The seam allowance is enclosed, the inside looks finished, and nothing can fray.

Binding is usually cut on the bias — diagonally across the grain — so it can bend around curves without puckering; on a straight seam a straight-grain tape does the same job and is quicker.

Why it was chosen

A flat-felled seam is the workshop's first choice for strength, but it needs a cloth that folds and presses cleanly, and it needs the seam to be reachable from both sides on the machine. A bag body, a curved seam, or a cloth like waxed canvas that resists being pressed into a fold are better served by binding:

• The inside of a bag is looked into every day. Binding makes it tidy without a lining.
• Waxed canvas will not take a crisp fold and marks when it is pressed hard; binding covers the edge without asking it to.
• A bound edge is easy to replace if it ever wears, without opening the seam.

Where it appears

The Field Tote's interior seams are bound, so the inside of the bag is finished cloth rather than raw canvas. The Chore Coat's inside seams are finished with cotton binding, which is what lets it be an unlined coat with a clean interior.

What it changes

Functionally, a bound seam is a little bulkier than a felled one and a good deal less bulky than a lining. Visually it is invisible from outside; inside, it is a line of contrasting or matching tape along every seam, and on a coat it is the thing you notice when you take it off. The binding wears in step with the cloth and can be re-done on its own.