New Build Advise Ive Got Myself So Confused ! Please Help !

[Web Goblin]

I built my frame from steel angle and the gantry from alu profile. While this works well for most of the stuff I have been doing it is failing to produce good cuts on some of the things I am pushing it to do now.
So the upshot of this is that I am now designing a new one made from steel box section.
For the most part the frame does not have to be perfectly straight, you can always shim it to get things level.
As for milling steel I wouldn't even think about it.

[EddyCurrent]

As for milling steel I wouldn't even think about it.

I think you used the key word there, "milling", for me I think of router for wood, plastic, foam, etc. and for metal I think of milling machine. When you look at some of the builds on this site though I can see how a router could tackle softer metal such as aluminium if strength and stiffness is built into the machine.