First, never use it in the bobbin. It rarely ever work. In order to use it on the top, I find that adding tension points along the path makes it behave better. By this I mean, Instead of just following the regular thread path on the machine, as soon as it comes out of the spool add another point. I put an older machine behind mine. I go from the spool wrap around the spool holder of the second machine, then back to my machine, and follow the regular thread. This extra tension point makes it behave better. Also, avoid sewing fast and stopping suddenly. The spool continues to unravel if you stop too fast and then it gets tangled on the spool holder. If you don't notice and continue to sew the thread will stretch and it will sew for a while before you realize it and when you stop it tries to shrink back again. Is not pretty. Don't ask me how I know. Sew slowly but steady. Give yourself practice time to learn to use it.