Serger

A serger, also called an overlock machine, is a specialized sewing machine designed to finish raw fabric edges quickly and neatly. Unlike a standard lockstitch machine, a serger trims the seam allowance, encloses it with multiple threads, and often produces a narrow, self-contained edge finish. This makes it widely used in garment construction, home sewing, and other applications that require fast edge finishing.

A serger uses several threads—commonly three or four, and occasionally five—passed through a system of needles and loopers. A built-in knife trims the fabric edge while the threads interlock around the edge to form an overlock stitch. Most domestic machines offer differential feed to accommodate different fabrics, and adjustable stitch width and length. Threading is typically more complex than on a regular sewing machine, though many models include color-coded guides and quick-threading features.

Common configurations include 3-thread, 4-thread, and 5-thread machines. A 3-thread serger provides a basic overlock for lightweight fabrics; a 4-thread model adds a seam and edge finish; a 5-thread machine often combines a two-needle safety stitch with the overlock. Sergers are particularly valued for finishing knit fabrics and for narrow rolled hems.

Maintenance involves keeping the blades sharp, cleaning lint from the looper area, following the threading path carefully, and replacing needles and blades as needed. Proper tension and alignment are important for balanced stitches, and some care is required to avoid injuries from the cutting knife when the machine is in use.

Historically, overlock and serger machines developed in the late 19th and early 20th centuries, with rapid advancement through the mid- to late-20th century. Today, major manufacturers such as Brother, Juki, Bernina, Janome, Singer, and Babylock produce domestic and industrial sergers.