here's a tip for those of you who use sulky thread (on a long or tall spool).

you can adapt a Rite bobbin to hold the longer spools by replacing the existing spool axle with a 3 inch long piece of 4-40 all thread. you reuse the nylon washers and nylon end cap of the existing bobbin, but then you want to mount a sandwich of a rubber washer, a small fender washer and a double 4-40 nut on the new 4-40 all thread. finger tighten and away you go. this is not an elegant, engineered solution, and it may affect your Rite warranty since it is not an approved modification, but the good news is it does work.

I have fotos; if you'll PM me your email I'll email you the fotos.