I have the D1. Some spools should be horizontal, others vertical. Also, I would take a piece of the top fabric, the batting your are using and backing and make an 18" quilt sandwich "sample" and use a different thread and see if it is still a problem. Process of elimination in the works. Then add the top thread and try again. Then the bobbin thread. A new needle, of course, and take the plate out and clean the bobbin & teeth area. Good luck. Gerry