If you didn’t know about the Ghost Gunner, now you do.
From GhostGunner.net: “Ghost Gunner is a general purpose CNC mill, built upon a large body of open source work, including the gshield 3 axis motion hardware, the grbl g-code parser and motion controller, and popular microcontrollers. All Ghost Gunner schematics and design files will be published into the public domain, and anyone can program anything for the machine.”