Quote Originally Posted by Hulksmash View Post
Would aluminium box section be the same as profile for how flat they can be ? I believe they are both formed the same way.

Many thanks
Aluminium box profile is not a good idea for this purpose. They twist and deform too easy and are not very flat unless special made with very thick walls. Especially once you start drilling holes in the box it will be noticeably worse. If you use aluminium profiles get 45x90 or better. My machine is built based on 45x90 but it is regarded as small, so it's OK for that. I mill aluminium, PCB as well as other, softer material, but my work area is 310 x 270 mm with a 150mm maximum Z. The total weight is about 90kg, excluding the PSU, electronics, wiring and the spindle. The foot print is 750 x 650mm, it is a stand alone type with fixed gantry beam, moving table.