Quote Originally Posted by mcardoso View Post
Did a bunch of deep bearing bores similar to what you're talking about here. Dial in the starting diameter to be very consistent then your finish pass will have the same deflection from part to part. Take your one cut and be done.

A solid carbide bar will almost certainly be needed here unless you want to run your lathe at 50rpm to avoid chatter.
Yeah I figured solid carbide is a must for this. I've been looking at some micro 100 boring bars and groove tools. Solid carbide inserted tools. Looks decent for the price. Some of them even have through coolant which wouldn't be too hard for me to rig up.