Seam finishing prevents a raw cut edge from continuing to fray during wear and washing. The method depends on fabric, seam, stress, and the desired appearance. Knits often fray less than wovens but may curl or develop runs.
Finishing on a sewing machine
A zigzag stitch alternates between the fabric and the area close to its edge. A domestic overcast stitch uses a compatible presser foot and denser thread path to support the edge. The fabric runs against the foot’s guide; turn the handwheel first to confirm that the selected stitch cannot strike the foot.
Width and length should secure the yarns without pulling the edge into a tunnel. Loosely woven cloth needs more support than a stable, tightly woven cotton.
Serger and alternative finishes
An overlocker or serger trims the edge and wraps it with multiple threads. Depending on the setup, it can construct and finish a seam in one operation, although it is not ideal for every corner or construction sequence.
Other options include:
- pinking shears for stable, lightly fraying wovens
- bias-bound or Hong Kong finishes for visible interiors
- enclosed edges in French seams or flat-felled seams
- a lining that covers the allowances
Before or after construction?
Allowances can be finished separately before sewing or together afterward. Separate finishing allows them to be pressed open; finishing both as one places them to the same side. Follow the pattern and consider later construction steps.
Finishing should not unexpectedly reduce the seam allowance. With a serger in particular, test how much the knife removes before working on the project pieces.