I am considering building myself a CNC router using the jgro plans. I would like to subsitute the gas pipe linear rails with drill rods. The drill rod is much smoother - I think. The rails will be used with skate bearings. After looking at McMaster Carr and MSC, I'm a bit confused as to which types of drill rods to choose. There are three types - air, oil, and water hardened. Which one? I would like to go on the "cheap" path (don't we all?) but it should be durable enough for the skate bearings to roll on.
Thanks!