[patrickt]

Yes, that's exactly what it was. What I did to find it was to put little 12v trouble lights, fastened by alligator clips, along the ignition switch to solenoid to starter line and watch them each time I started the car. Sure enough, one time I tried to start the car and the trouble lights showed no current whatsoever on the starter pole of the switch, much less at the solenoid or anywhere else downstream. By carefully jiggling the switch, I was able to get the lights to come on and the car to start. Bob P. sent me a new switch, gratis, that had been re-threaded to use the fancy bezel. No problems since.