Sometimes I'll lay in bed at night after an episode like that and I'll think of all the thing it might be. The next morning I go in and check ALL of those things and usually come up with a solution. Frustration requires a "rest" period. BTW, don't know what kind of thread you are using, but I've tried some of the cheaper threads and found I have all kinds of problems with skipping and breaking. I think long arms are very picky! Mine likes King Tut on the top and Bottom Line in the bobbin. If you are using a cheap thread for your charity quilts, you might try changing and see if the breaking stops.