I have the Brother Nouvelle 1500s. Mine will sew with any thread I stick in it which is generally some cheapie stuff like Maxi-Lock serger thread or Coates and Clark. I have sewn with assorted metallics, too, with no problems. Is there any chance your problem is something other than thread? Is it threaded properly? I had a few issues the first couple of days with threading. PM if you think I can help further.