Hope I'm not committing an RTFM error here
I want to build a 3D CNC router with roughly an 8" cube of swept space. I have my own steppers (#43?), over a dozen 3/8" dia. linear bearings and 3/8" precision shaft and my own machine shop (lathe and mill).
Can you point me at a suitable gantry design that I can use or modify. I plan to use it for multiple purposes (e.g., RepRap-style plastic extruder head, engraving metal scales and dials with a Dremel tool, air-powered spindle or somewhat heavier head). Thus I would like the structure to be as stiff as possible and capable of holding position in spite of vibration or head weight to within 0.001". (Backlash to be controlled by preloading, for example.)
Engineering analyses, real-life experience, etc., are a plus.