Construction has started on the frame for the CNC mill. I was able to talk a coworker into cutting the 8020 for me using the metal saw at my work.
I've realized that I don't have all of the corner pieces and other connectors. For sure, I'll be 4 short of the "15 Series 12 Hole - 90 Degree Angled Flat Plate". I'm using the "15 Series & Ready Tube 5 Hole - 90 Degree Angled Flat Plate" with some extra "Inside Corner L" brackets for extra support. If this will stay rigid, I shouldn't have to do anything extra. If not, however, I will have to look at buying new pieces.
I purchased all of the 8020 from my employer. They upgraded a robot arm and it came with a new cage. The old cage was removed and auctioned off.