BTW hoo flung, if you're fussing with a critical dimension you're wasting time.
Critical dimensions are designed to be produced by the quickest means possible, and this means either centreless grinding etc for outside diameters, or reaming and honing for bores.
Unless of course you are only making one part at a time, then you won't be making any money anyway.
Some people I knew had the reputation of making jobs that were gold plated.
Ian.