Overlock thread is used for finishing, or overlocking, heavily frayed fabrics, as these would otherwise fray into the seam after several wears or washes, resulting in visible holes in the seams. It is thinner than regular sewing thread, yet very tear-resistant. Because overlock and cover stitches require much more thread than those sewn with a home sewing machine, overlock threads...

Bulky yarn is made of air-formed polyester silk and is not twisted. Therefore, it is softer than regular yarn. Even though it is used for stretchy seams, the individual fibers are not inherently stretchy. The stretch is created by the crimping of the individual threads and the resulting fluffiness. Due to its soft, fibrous structure, bulky yarn lies much more comfortably when sewn. Cover...