I did an initial mounting of the rails to check for parallel when using the two reference edges that I milled. With minor tweaking of the secondary rail, things look good at first glance. This is only a 0.0005" indicator, and there is a tiny amount of movement probably on the order of 0.00015 (~3.8 um).



I didn't spend a lot of time with this because I had to pull the rails back off to do more machining for the ball screw.