hi matt , let me try to explain a little better,,, there is nothing wrong with the thicknes of the shaft niether in the main part or the bottom narrow part,its the flat piece between the 2 that seems to be a little off,,there is what looks like a score mark from the machining that goes off at a very slight angle so when the shaft is sat down in the bearing the flat underside on teh mainshaft looks flush against teh bearing one side but slightly raised the other