OK - I'm stabilising the edge of a quilt before binding and my top thread keeps breaking. Tension is set where it always is for this - 3.5. I changed the needle for a new one, I even tried a different spool of thread in case it was 'faulty' although it's the same brand I always use and never had trouble before. And I unthreaded and rethreaded in case something was wrong there. It sews for about a foot then snaps! Grrrr! I'd just SID quilted the whole quilt with it - no problem; it's a new (to me) machine I recently bought off a friend and I can't believe it's faulty; any ideas, anyone?