some are listed on diverse articles of Hackaday.com
a community organizing around the open hardware concept is gathering at http://openbuilds.com mainly using “off the shelf” but specialized components like aluminum extrusion, many open source CNC milling machine and 3D printers designs are available. Use it as inspiration for wood design of pieces.
see on reprap.org wiki
Hosni is working on a custom board as Study End Year Project, more information here later…
for a CNC capable of cutting at production rates, we need equivalent of NEMA23 or bigger motors to drive the axis. ⇒ 30V4A class driver needed, exceeding the classical 3d printer setup that don't need powerfull motor for action. Can be usefull for other type of mechanical setup like robot harm, seat simulator, roomsize printer, or cable robot(http://hackaday.com/2015/09/21/3d-cable-robot-uses-the-building-as-its-exoskeleton/ and http://hackaday.com/2015/09/24/cables-and-winches-become-an-awesome-simulator/).
the opensource ecology group build a CNC torch cutter in metal, and powered it with this
interesting technique to mitigate cogging in BLDC motors : http://modlabupenn.org/anticogging/
source : use with Inkscape with Gcode plugin
based on bicycle gears and chain for easy sampling and replacement
this software can be useful : https://gitlab.com/damien.andre/openmeca