I recently got my machine back from the repair guy that comes in to Joann's to fix machines. He accidently left a bobbin in my machine. It is thicker than the cheap bobbins and holds more thread and has about 8 holes around both sides of the bobbin. I had the same problem you have with bobbins until I used his bobbin. My thread does not jump out of the bobbin case with this new bobbin. I'm on the hunt for this new found bobbin the repair guy left in my machine.