One of the more important, but less interesting parts of this CNC build is creating a flat and level surface to assemble the machine on. Since the machine is significantly heavier than my Shapeoko 2, the table structure needs to be strong enough to be part of the CNC frame.
To accomplish this I built the table frame out of 1" x 3" x 1/8" aluminum rectangle tube. The tabletop is 3/4" MDF, and I think the final dimensions are approximately 4' x 3'. I originally planned on using 4 x 4's for the legs, but was unable to get anything satisfactory from my local lumberyard. I settled on using some rather thin angle steel for the legs, but there's a good chance that I may have to change them out for something sturdier in the future, check out the video and you'll see what I mean. However, maybe I can figure out something to sturdy the legs up, but until then the jury's out on whether or not they'll be permanent.
As far as flatness goes, I think I did fairly well. I purchased a fairly nice level with a milled surface. Using the level I don't see any high or low spots on the table surface, so I think I did okay.