When a “bird’s nest” of thread appears … the likely culprit is your upper thread tension. If loops appear on the underside of the fabric, the upper thread tension may be too loose. If knots appear on top of the fabric, the upper tension may be too tight.
Ever want to pull your hair out because your serger threads "don't look right"? Complete this simple sewing exercise, and you'll never wonder which dial you need to touch! I now have my tension dials set to the perfect numbers.