I had a nightmare bobbin issue one time. Took my new Janome 6500 to a class after using it just a day or two. Ran out of bobbin thread in the middle of the class and a friend offered me a pre-filled bobbin. From that moment, I had problems with the machine. Silly me worried with threading and rethreading and finally just gave up and took it to the dealer the next day. Guess what - a Brother bobbin will not work in a Janome! Boy did I feel stupid!!!