What type of machine stitch is ideal for sewing knits and stretch fabrics?

The overlock stitch is ideal for sewing knits and stretch fabrics because it is specifically designed to accommodate the stretch characteristics of these materials. This type of stitch allows for a combination of both seaming and finishing the edges of the fabric, preventing fraying while allowing the fabric to maintain its elasticity. The overlock stitch generally has a looped thread construction that secures the edges of the fabric while also providing stretch, which is essential when sewing knits that can move and expand during wear.

In contrast, a straight stitch is rigid and does not allow for stretch, making it unsuitable for knit fabrics, which need flexibility. The zigzag stitch can offer some stretch but is not as efficient as an overlock in providing a clean finish and securing raw edges simultaneously. A basting stitch serves a temporary purpose and is not durable, making it irrelevant for the construction of garments made from stretchy materials. Consequently, the overlock stitch is the preferred choice for dealing with knits and stretch fabrics due to its functional advantages in both seam construction and finishing.