Well, I have made threads about possible builds, but never followed through. Not this time I have my steel ordered, I have a welder friend to assist with the build. Router frame to be fabricated from 2" , 1/4 wall, steel tubing. Heavy wall I figured better for any drilling & tapping. , 1/8 wall. I currently have 25mm round rail & bearings, free, though I may purchase 20mm profiled linear guides, The working envelope will be 50 x 50 inches, I wanted to have no issues with a 48" board. I have nema34 steppers, free also, I located a data sheet on them, but I do not recall the specs, They originally came on a Vortech CNC. The gantry beam will be 3060 extrusion, with 3/4" 6061 aluminum uprights & bearing mounts. Building to get between 6 & 8 " of gantry clearance, my design is not final. I have not yet purchased a BOB, but I plan on using UCCNC as a motion controller. I have enough steppers & drive to build a rotary axis also. I also have a base designed, though in my pics it is rendered as 4x4 lumber, I will likely build from 4x4 steel tubing as I may use this on the road with my job. Which frame version do you guys think I should go with from my pics,

Fusion360 Models of the pics are located here
Pic 1 - A360
Pic 2 - A360
Pic 3 - A360