I would be very sure about your bobbins. Just this afternoon (knew this subject would come up, I'm a mind reader, just wish I were a quilter instead) anyway. On my machine table I have my Bernina 630 and the other table I have my Expression 3. Pfaff. Since I had a new project going on the 630, I took my threads and bobbins that I had been using on one particular project and decided I would finish it on the Pfaff. Piece of Cake. WRONG! I had everything loaded and threaded perfectly and had my little scrap starter and wanted to make sure my stitch would be the same. Well for the life of me I kept jamming. I double checked the way the bobbin was in, check the top thread, etc. and it would stitch a bit then jam. I got up from the machine walked around the room and then sat back down, popped open the bobbin tray and removed the BERNINA bobbin and sit it off to the side and then took a PFAFF bobbin, filled it with thread, replaced it in my PFAFF machine and i proceeded with just the prettiest stitches you could want. And now while I start dinner, I am going in the Pfaff to finish up the last of the table topper that I am making for a friend. Another hint. If you are using plastic bobbins such as on the Pfaff, the Viking and a few others. When you are filling a plastic bobbin, speed is not your friend. If you put the petal to the medal so to speak, you could cause the thread to wind so fast that it will actually tighten the plastic bobbin and then when you are done, you cannot get that bobbin off to save your life. You will have to manually unwind the bobbin until you finally reach the stress point, and it could all of the thread sometimes, before you can actually get the bobbin off. If there is something that can go wrong for the dumbest reason, just call me.. 1-800-ask-blue. hugs