I'm going to build a desktop mill and want to be able to machine aluminum and steel with a good degree of accuracy. I'm going to be using THK linear rails and bearings and ballscrews.

Question: Any thoughts on using a section of 4 inch, thick wall (.25 or so) square stock as the mill uprights with welded and faced steel pads. My idea is to fill the square stock with concrete to stiffen and dampen any inherent resonance the steel tub might have. Any one tried this? Any thoughts?

Larry in NC