This CNC machine design uses readily avalable 8020 extrusion as the main construction element. (click machine on right for larger view) In this case it is a Maytec product. The machine has high accuracy, without the use of costly materials.
A core feature of the design is the facility to customize the resulting CNC machine to builders own requirements. It can be built as a 3 axis configuration and easily upgraded to add use of rotary axes. It can just as easily be built as a full 6 axis configuration from the outset.