Design brief

Primarily my interest is in building a machine for woodworking, for both cutting large parts and doing basic relief carving. I am limited in size by my available workshop space, but want to be able to cut parts from a quarter sheet of ply, i.e a cutting area of at least 2x4 feet. Lots of machines have been built using MDF (Medium Density Fiberboard), it is structurally very stable and relatively inexpensive, the other option is 80/20 aluminium extrusion, which is extremely structurally stable but relatively expensive. Due to budget limitations, and my existing woodworking abilities, MDF was the obvious choice.
After a lot of research on cnczone forums I chose two builds on which to base my design, the original being by Grunblau, the second based on this build was by Turbo1zz. From the forum posts I was able to gather a lot of information and set about making my own detailed designs.