You can, but you'll get much better results with threads designed for sergers. Regular sewing thread works in the needle positions, but it doesn't create the same soft, smooth coverage in the loopers that serger-specific threads do. Serger threads like Woolly Nylon (for the looper) are designed to spread and fill, creating those professional-looking edges without bulk or stiffness. Plus, sergers use a lot more thread than regular sewing machines (you're using 3-4 cones at once!), which is why QuiltMaker is an excellent needle thread, so the large cone put-up of serger threads means fewer interruptions. If you're in a pinch and need to finish a seam, sure, regular thread will work. But once you try real serger thread, you'll never want to go back to regular thread.