Atlas Mill arbor runout

[JPMacG]

I had some time today to make better measurements. The total indicator runout on my bare arbor (without the cutter and spacers) is under .002. I checked both ends and the middle - and they are roughly the same. Also, to answer RobertB's question, yes, the cyclic cutting is the same for all my cutters.

I am concluding that, as JCP said, it is the nature of the beast. I need to take deeper cuts, or increase the feed rate, or both.