Best Industrial Sewing Machines for Activewear & Knits

Two: an overlock (serger) to seam and finish the stretch fabric, and a coverstitch for the flat, elastic hems and topstitching. The overlock's differential feed keeps knit seams from waving, and the coverstitch keeps hems stretchy so they don't pop. JACK's E4S overlock and K5 or W4 coverstitch machines cover this work.

An overlock wraps and trims the raw edge with two to six threads to seam and finish stretch fabric. A coverstitch sews two or three parallel rows on top with a looper underneath to make a flat, stretchy hem. You generally need both for knits — the overlock builds the garment, the coverstitch finishes the hems.

For open, flat hems the W4 flatbed coverstitch is the straightforward choice; for tubular pieces like cuffs and sleeves the K5 cylinder-bed coverstitch wraps around the tube. Both offer thread-trimmer and auto-footlifter options. They're linked below with full specs.