I took me a long time to figure out that under my magnetically attached spool holder/shuttle junk had built up allowing it to jump off the magnet, but only at high rpm, breaking the needle. BTW, when I went to school, you had to take Home Econ to graduate, and I learned to use sewing machines, utilizing sewing patterns and common tools like tracing paper, with a final project, as well as demonstrate many hand stitches. I wished my children would have had this opportunity.