Changed the needle-apparently 15x1 is the correct one. It's not catching on anything, but it's also not picking up the bobbin thread, either. Both old Kenmores have a funky bobbin case with the tension spring on the finger, and that's where the upper thread is hanging up, I think. I'll fiddle with it some more, but I'm also going to my osmg's tomorrow, to take him the current batch, and this one for a rewiring. He said he'd check out everything else while I was there, so one way or another, I'll get this sorted!