Im going to get some Bosh 90x90 alu profiles, so Im going to use them for the main frame. Solid/stable frame I think 
it seems to work for them https://www.cnc-step.de/
How come folks go with these 8020 type extrusions? Is it that you don’t have the machinery to work with steel stock? Or is there some other advantage with using these profiles? Stuff seems kind of toy like to me. That might be the appeal? I am just curious why people go this route.
This is my first CNC build, and I do not have the tools to work with steel. Using profiles like this I`m able to build an ok CNC using the tools I have + I did get a great deal when purchasing the profiles…
@Oyvind_Amundsen
I suspect a lot of people go with these profiles for ease of use. If they’re cut for you square, and the right length, then assembling them is a no brainer. You can still screw it up, but it’d be hard. Even if you did manage to put it together out of alignment you could always realign it.
I guess I`m going to alter the design some times before I start the real work. I get new comments… all the time about things I should alter… It is great that I can use software like Fusion 360 to test ideas and do corrections until I have the design I want to use.
I have found with aluminum profiles having a good flat hard surface to assemble it on works best to keep all on same plane well you tighten bolts.
@Oyvind_Amundsen
failing to plan is planning to fail. Although with a project like building a CNC, if you’ve never done it before, things are bound to crop up that you don’t anticipate. I was watching a video on YouTube of a guy that had build hundreds of CNC machines and even he forgot some details.
When I built mine I figured it out as I went along. I would get to a point where I had to mount something, then I’d draw out how I was going to do it. Based on measurements I’d take. I had some parts I was reusing from an earlier design that did not work right. So a lot of what I did depended on the dimensions of that.
I did all of mine using pencil, and paper. I can’t stand CAD software. The folks that make that stuff don’t know the first thing about drawing. Or if they do, it sure doesn’t show in the user interfaces they come up with.