on your machine. I know this sounds funny but sometimes the bobbin is not the exact one that goes in the FW. Sometimes it is just a tad to big. Try a new bobbin. Also you can call the singer company, give them your model number etc. of your machine and they can mail you a copy of the book that goes with it for a fee. Well worth it. There is really not much that can go wrong with the FW I would buy it but try to get the price down some. Hope this helps. pat