Bulky nylon is the same as other manufacturers' wooly nylon. It is stretchy so that it fills in the serger stitches when it relaxes and creates a nice edge when you narrow hem or roll hem items (like napkin edges). I've only used it on the serger for rolled hems and it's great for that. I don't know what it would do in your DSM but I'm pretty sure the tension would be a nightmare.