I commend those who are building their own CNC and wish you good luck with your projects.
In looking at prebuilt models, there seem to be two different construction styles; welded and screwed. Since you are using 8020, you fall into the screwed together construction style.
My question is, what are you doing about guaranteeing the screws don't come loose after many hours of use and lots of vibration? Any special locking nuts or are you using Locktight? Red or blue?
I also teach AR-15 building and Locktight is one of our best friends.
Sunny San Diego, Kalifornia