RV converter/chargers are throw aways. Also, did you check the battery for water? The chargers are supose to 'float charge' but batteries in RV's need to be checked for water at least monthly.
I would try to preserve any thickness if the replacements are more than you want to spend. Grooves or ridges? If the rotor is OK exceptfor a ridge on the OD then yea turn away. Just grooves in the rotor, don't take more material off just to make the surface smooth.
One more thought on the installation. A few taps with a rubber hammer may not be seating the taper. Clean the two parts and reseat with a real hammer 16-24 oz and a piece of hard wood or aluminum between the chuck and shaft. Open the chuck so the jaws are flush or below the chuck...
Does the chuck spin true or wobble? Sideloading can displace a chuck taper. The other thing is the taper bottoming out before the taper sets? Clean the end of the taper and mark it with dye/ink and see if there is a wear mark. If that is the case, grind the end of the taper a bit...
I think ANY lathe is better than no lathe BUT, the known limitations have to be considered. If you are only going to use this for small parts of low strength materials with the expectation of spending lots of time and money to make anything. If the OP is only going to use this once in a...
I would not trust that 'hoist' to lift more than a couple hundred pound at most. I have three half ton jib cranes and they make that look like a coat rack.
The crane in the pic is a half ton jib, it is on an 8" heavy I beam that goes from floor to a roof beam.
This is a long shot but, anybody have or know of a motor pulley for a 20" 1100 mid 1940's vintage. The largest step is about 8.5" in diameter and the shaft bore is 5/8.