My Janome machine won't take either YLI machine quilting thread or Superior King Tut - they're too thick and jam in the tension discs (and believe me, I've tried every possible tension setting). I assumed that it must be a quirk of that machine, as if they're sold as machine quilting threads, they should work on a machine - right?! I've just bought a Singer 201, specifically for FMQ because of the problems with the Janome, and am very surprised and disappointed to find that I've got exactly the same issue. Do other people have this problem or have I just been very unlucky?