I had that problem with shredding and breaking on my Designer I. I suspicioned (sp) that the thread was dried out. I placed wet paper towels on top of the spools of thread that were stored in a closed plastic container. I left them for a couple of days and Bingo. My problem was solved. I now keep a damp towl inside the container most of the time. I would keep them in the frig or freezer if I had the room. Did that some time ago when I was doing a great deal of machine applique. This might help you. Oh, I also use topstitch needles. Good luck. Marge L.