Originally Posted by
Tartan
Are you pulling the bobbin thread to the top of the sandwich and holding both thread tails as you start stitching? If I don't do that I sometimes get a thread nest underneath my work. Does your machine wind your bobbins well or are some if the bobbins not wound correctly? Have you cleaned your bobbin case out well and put a drop of oil on the bobbin hook if your machine manual calls for it?
This was my thought also.