Well after years of inspiration, figured I should give back to the community by documenting my own build. The plan is to end up with a vertical mill that mills aluminum and some steel. Overall work volume should be about 19x10x14 inches X Y Z with future 4th axis. I had been considering gantries and other nonstandard layouts but finally decided on C frame for manufacturing simplicity.
Spindle is a mini mill run by a 1.5 HP treadmill motor. I feel this to be the weak link so far, but it's what I have on hand presently and in the future could be switched out.
Ballscrews are from our favorite Chinese manufacturer of cheap rolled precision ballscrews. For some reason there's alot of drag on them (like hard to rotate the nut and screw by hand) I'm attributing to tight rubber seals that hopefully loosen up since they spin fine without em. Linear guides for Y and Z are 2 each NSK 35mm 4 way contact long blocks with high preload, and 25mm THK on X.
Main structure is 8x8x3/8 and 5x5x1/4 steel tubing with an E/G sandwich between to help dampen vibrations. Total weight should be around 700lbs, lightweight for the work volume but hopefully the choice of materials and FEA simulations will keep things stiff. Using surplus flat ground 3/4 steel waterjetted for various mating plates, and then epoxy/metal powder to level the way surfaces on the steel tube. Still trying to find an answer on how necessary stress relieving is on these A500 steel shapes. Id like to weld em together but again, stress relieving on such an ungainly structure may be costly. The table is a replacement from a 8x28 HF mill, only like $130 to my door, not too shabby. Overall trying to avoid milling parts since access to machinery is limited, at worst there is a pay per personal use shop nearby (I'm in Dayton Ohio).
Controls provided by Mach3 and parallel port (I hear that's the most reliable Mach setup) I spent the last 2 weekends wiring up the enclosure and got my motors to spin! Zeta4 drives will push about 400W through some Nema 34 steppers from Lin Engineering and compumotor (love not having a giant transformer). Kinda a waste having such high quality motors attached to high quality drivers, the anti resonance driver settings seems to overlap the Lin's superb rotor design, didn't need any of the damping settings which were necessary for the old compumotor stepper, but hey they were all cheap ebay buys so it's all good =p
Oh yeah, and I'm pretty commited now since the steel and ballscrews are cut to length, we'll see how fast progress is.
Enough chitchat, here's some eyecandy: