The X gantry is rolling on the 3 1/2" pipe rails today. The y rails at the top of the x gantry are deflecting about .030" (with feeler guages) under the preload of the tensioners, see pics. You can see a little light between there.
I will have to fabricate a tension rod truss piece for underneath these 2-1/2" pipe rails to take that out. Other than that, it is rolling very smoothly. I wanted to make the end connections adjustable so the checking & wracking due to moving the table around & welding could be calibrated & it's trussed to keep the weight down.
At first I located both adjustment bolts (both the compression pipe & the two 1/2 threaded rods) on the lower end where the rollers are, this allowed the roller bracket to twist under its own weight ever so slightly.
I realized I should have welded the compression pipe at the lower end to take out the moment stress & put the adjustment bolt at the top. It is much stiffer this way.
More next week
Cheers.