Though he did say "under the misapprehension that a CNC machine will automatically produce more accurate work than a manual machine" which I don't think really conveyed what he meant well. What I took it to mean (and what I think intended) was that doing it on a mill isn't the right tool to machine a shaft and then a hole on the opposite end concentric and parallel. On a lathe, with the procedure Hoss outlined, you'll get very high concentricity, thus eliminating shaft runout. On a mill you'd be very hard pressed, CNC or manual to keep both ends concentric and parallel with the changing around of parts setup. That's not saying it can't be done, but I'd personally do it on a lathe.

One question for Hoss - did you use carbide/HSS tooling on the arbor or did you use a toolpost grinder? Just curious after my experience with grinding the ballscrew shafts in my conversion.

Greg