To make a CNC machine, you could use V Slot openbuild extrusion.
It uses V Slot, commonly used in 3D printers.
It uses 3 motors, at least.
It has a toolhead, which should be replaceable/removable/interchangeable.
Size can be planned upto 4 by 8 foot
Angle grinder mount, for precise cutting of metal
Drill holder, for more precise drilling, vertically and at angles