[Arran]

Warping pot metal in the tuning capacitors seems to have been a problem with many American Grigsby Grunow Majestics from that era, I haven't run into that problem in any Canadian Rogers made Majestics from those years though, even though the chassis and circuits are very similar. There are ways of repairing the problem apparently, although as with anything like that it isn't a job for those who are not mechanically inclined or have experience with such things.
Regards
Arran