I have the Sapphire 835 and I do lots of quilting; its a new machine to me; I have no trouble doing the free motion quilting if I use the 80/12 needle; coats & Clarks quilting and piecing threads which are a 35wt blend - my problem that I would live input on is how do you do free motion with other threads; for instance I just bought a set of the Rowan threads - a lovely color range and weight of thread and I want to do some "art" quilting with them but the thread breaks constantantly. I have tried several tension settings and different needles and can't seem to get it to work. Does anyone use heavier threads for quilting with this machine free motion and have any suggestions? Thank you.