8020 extrusion dimensional accuracy

Not sure if this is the right sub, please let me know if there is a more appropriate one.

Recently scored a great deal on a lot of 1530 (1.5" x 3") 8020inc extrusions. 16pcs, 48" inch long , 8 regular weight/smooth, 8 lite/ridged, all anodized black

I want to build a modular, general purpose setup table.

Doing mostly woodworking at the moment but may do a CNC gantry at some point (which may or may not be extrusions itself), but at the moment I just want a reasonably flat surface with some t-slots for holdown equipment.

Any general advice?

I am thinking I will do a perimeter of vertically oriented extrusions (3" face outwards, 1.5" face @ working surface level) with some intermediate extrusion members running cross-ways (3" faceup @ working surface) with MDF sections between. Also extrusion for legs with the faces planar with the outer perimeter.

One concern I have is how to connect them squarely. The extrusion seem quite straight, but the faces are not very flat. E.g. measuring the max thickness I get 1.500 right in the center but as little as 1.495 outside of the t-slots, so it seems if I bolt up a flat angle connector it will a bit skew, enough to give 0.25" runout over 48" (by my simplistic reasoning)

I do have a small desktop CNC mill and I could flycut the faces, 18" at a time, but that would a pain, and I would loose the nice anodized finish.

Could it be the 2 degree incline you are measuring?
Larry

I called my self measuring the maximum dimension, I put the jaw across the whole surface.