Overlockstich

The overlock stitch, commonly called an overlock or serger finish, is a sewing stitch produced by an overlock machine. It trims the fabric edge, encloses it with thread, and often joins two fabric edges in a single operation, producing a neat, stretchable finish that resists fraying. It is widely used on garments and home textiles.

Construction: Overlock stitching uses multiple threads—typically three to five—and one blade that trims away the excess edge. The machine feeds the fabric with differential feed, and loopers wrap the edge with upper and lower threads. On woven fabrics it can create a tight seam; on knits it allows stretch. The result is a finished edge with a characteristic rolled or chain-like appearance along the seam.

Variants: A 3-thread overlock uses two needles and a looper to finish and sometimes join; a 4-thread overlock adds an additional needle for a stronger seam; a 5-thread variant combines two upper threads and two lower threads for a wide, safe seam. Rolled hems produce a narrow, clean edge for lightweight fabrics. Some machines also offer adjustable knife and differential feed to tailor edge finish and prevent puckering.

Usage and considerations: Overlock stitches are common in garment construction, especially for knit fabrics and interior seams. They are not a substitute for straight stitches in all situations; final choice depends on fabric type and desired durability. Proper tension, blade settings, and maintenance are required to avoid skipped stitches or fabric damage. The term serger is often used in North America and overlock in Europe and other regions.