While I was at a workshop, the instructor talked a little an thread. With that, she told how her machine with a thread cutter doesn't like certain threads, and won't cut them. One of the gals was thrilled when she said that. This gal retried her thread cutter, and was doing the Happy Dance, because it worked. She told us that it hadn't worked in years, and she recently started using different thread. She retried using it and the thread cutter worked. She was especially happy with the class!