[DonRotolo]

This was what I ended up building, based on the Nuts & Volts articles: A custom 3-axis CNC controlled milling machine. I have it configured as a PC Board drilling machine, but I just need to change Dremel bit and the hold-downs on the table and it'll mill whatever. Slowly.

What the pictures don't show is that it's mounted on a cart, with an IBM PS2 PC (8086 processor, with 8087 math co-processor, 4.77 MHz, 640k RAM, bad HDD and 730 k 3.5" floppy drive).

The first photo shows the overall work area. Travel is X=9.75", Y=10.5", and Z=4". Speed is about 3" per second max, when drilling this is not bad, for milling it takes forever. Precision is 0.00025, accuracy is about 0.005 in 10", repeatability is +/- 0.002 inches. Note the Dremel mount for the Z axis. A Roto-zip could also be mounted there for milling, has a LOT more power than the Dremel.

Sure beats drilling by hand.

The second photo is a close-up of the Y axis. Note the end-position (home) switch, the red plastic no-backlash nut, precision lead screw (about $15 for a 3' piece), the rubber hose coupling the screw to the motor shaft, and most importantly the "drawer slides" used for the X and Y axis rails.

It has about 100 hours on it and still works great. Nothing has broken yet.

Don