Then don't forget the power supplies, wiring and connectors. When you build out of wood every time the humidity and temperature changes so does all your build. Not much just a 1/8 inch or so, out of square or it binds in the middle of a job and it misses steps. There is someone in the business who purchases China CNC made routers, strips off all the crap controls, and installs a Acorn system, upgrading the rest as he goes. That way you start with a working machine (sort of) and have something working when your done, instead of 2x4's and plywood.