No threads yet. Using hardox 3/16 and some quarter I think. The Dog house above the ram is mild steel. And using .045 dual shield and .035 hardwire....
if ya wanna really check if your saw is cutting square, get a piece of square tube (I like to do this with 2"x2"x1/8" ) set the blade so its trimming...
But the actual problem here is that your engineer used architectural-aluminum rather than structural aluminum. That is why the corners separated like...
Then definitely do not try an extremely difficult repair. Mig or spool gun is not the dream tool to repair that in the first place, it is used mostly...