Well, this is my first home-built CNC machine, so I am just trying some stuff. Actually, while the rails are set in epoxy to create a conforming mounting surface, I had put some silicone grease on so that the epoxy does not stick and I can remove them if necessary (I hope....)
Yes, that is what I meant. I will probably map the x-y position error with a microscope across the table surface when the machine is complete. Then I could program a separate postprocessor for the G-Code to transform the coordinates and eliminate the repeatable errors. One of the projects I am planning to use this machine for is plastic gears that need to be pretty precise.