Tool For Skimming Commutators
Years ago I was given a tool and asked to make two more. I have no idea who's invention it was, but it saved many hours of work and was simple to operate.
The tool was designed to fit into the opening above the commutator and as the comy rotated, the tool was moved across the brass surface and cut a new surface.
It was a box that fitted into the housing above the comy. It had a side plate that was adjustable within the housing that when screwed out held the box solidly in the generator housing.
The housing had a 40TPI shaft, that held a ¼ inch tool bit that had in turn a screw lock on the tool bit. The depth of cut was adjusted in this manner. The 40TPI Shaft was wound across the comy as the generator was running. This of course skimmed the commutator.
It was very easy to do and saved pulling the generator apart and turning it in a lathe.
These generators were the type that was usually 25KVA upwards.