Checking the mainshaft is easy. You have a dial indicator? No? Use your eyes. Heck you can MAKE V blocks out of anything......wood. Lay the shaft in there so you can turn it. make a simple pointer. Drill press? Perfect. Lots of ways. Bring the pointer down close, turn the shaft, watch for wobble.
This will tell you TWO things......whether the shaft is really "warped" and how honest your rebuilder is
