I just made one - turns out it's really easy and pretty cheap! Who'd have known? Basically you just follow the instructions the RC guys have worked out (link below) then make it a bit bigger. All in about £250 and with some mods it'll turn into a light duty milling machine - should be good for milling foam & ply & plastic. https://www.rcgroups.com/forums/sho...Wire-CNC-(Arduino-Ramps1-4)-Complete-Solution Should make mould making really, really quick, simple & accurate as well as cutting cores for control surfaces etc.