I would never piece or sew a quilt with serger thread. I only use the best cotton thread I can find. First, serger thread is only 2 ply and short fiber. Sewing thread is 3 ply and long fibers. If you haven't read about thread, go to Superior threads and read about each kind, then you will understand why we have so many different kinds of thread. I would only use serger thread in the serger or if I was wanting to make something for a one or two time wearing like Halloween costumes for kids.