Hello,

Long time peruser of this site, first time poster. My background is a combo of furniture manufacturing & computing / web development and i'm currently working on setting up my own furniture workshop. Would much rather build my own CNC(s) than buy one, mostly because I really really want to, and also because i want the flexibility in the future of modifying or extending them as the production processes evolve.

Starting off I want to build a gantry style router that can take boards up to 8x4', and realistically i think i'm really going to be wanting 5 axis (i.e z, a & c axes on the gantry head, if i'm getting my axis labels right) Which going by picture on the internet looks difficult but definitely doable?

I'm also thinking to build a smaller machine for milling metals, to be used mostly for stainless steel and aluminium. Haven't decided on the size or the style of machine so plenty of questions to follow on this one! Presumably building the smaller machine first makes more sense as then i can use it for any milling i want done for the second machine.

My main first question is about the frame / gantry: there seems to be a fair few steel framed examples on here and I'm thinking this is the way to go (especially for the milling machine); Mild steel is cheaper than aluminium and not particularly difficult to work with. Is there a particular steel type / extrusion process that i should be looking for in terms of size tolerance and rigidity etc? I know distorting is also an issue if i weld the components together so am I better to bolt joints as much as possible and weld in short bursts where i have to?

If some more experienced people on here could give me their blessing on this approach to the frame (or suggest a better one!) Then i'll go away and do some proper CAD models.

Thanks everyone in advance for your wisdom!