[Arran]

Jayce;
Yes if the set has a gear reduction drive for the dial then hardened grease would be suspect as well. I once had a tuning shaft, with no gear reduction, that was very stiff, but not seized, I never went as far to take it apart but squirted some WD in the bushing and it loosened up within minutes. I have had others that I had no choice but to take apart as they were stuck, again hard grease was to blame, although mice urine likely contributed in the last one that was that way, it was a good thing the shaft was brass.
Regards
Arran