Overlock

An overlock, commonly known by the name of the machine that produces it, a serger, is a kind of stitch that sews over the edge of one or two pieces of cloth for edging, hemming or seaming. An overlock sewing machine will usually cut the edges of the cloth as they are fed through, though some are made without cutters, and the inclusion of an automated cutter lets the machine create a finished seam quickly. An overlock machine differs from an ordinary lockstitch sewing machine in that it uses loopers fed by multiple thread cones rather than a single bobbin, and those loopers create thread loops that pass from the needle thread to the fabric edges so the raw edge itself ends up enclosed within the seam.