Overlockers

An overlocker, also known as a serger in North America, is a specialized sewing machine designed to finish fabric edges and prevent fraying. Unlike a standard sewing machine, it trims the edge as it stitches and typically produces a narrow, finished seam suitable for knit and woven fabrics.

Operating principle: An overlocker uses several threads and one or more loopers to encase the fabric edge with a wrapping stitch. A built-in knife trims the edge just before stitching, creating a clean, consistent edge. Modern machines can operate with three, four, or five threads, and can form rolled hems and other stitch types.

Types and features: Domestic/household overlockers are generally lighter, slower, and offer 3- or 4-thread configurations with differential feed to accommodate fabric stretch. Industrial sergers are heavier-duty, faster, and may provide more thread configurations and independent tensions. Settings include stitch length, knife position, and tension for each thread.

Uses and technique: Overlockers are widely used to finish raw fabric edges, sew seams, and produce durable, stretch-friendly stitches, especially on knits and woven fabrics. They can create rolled hems, narrow hems, and flatlock seams. Threading a serger is more complex than a standard machine and requires careful following of the thread path; safety rules apply around the cutting knife.

Maintenance and considerations: Regular cleaning, oiling per manufacturer guidelines, and occasional blade replacement keep a serger functioning. Proper threading and tension setup are essential for reliable stitches. Availability ranges from budget domestic models to industrial machines used in professional garment production.