I recently got my CNC machine fully working! There's a lot left to improve upon, but I figured I would post a video of it in action. It uses a stationary gantry with a movable base, and the working area is about 1' x 1' x 4".
[nomedia="http://www.youtube.com/watch?v=wFLmq2fVUz4"]YouTube - Marc's CNC Hobby Router[/nomedia]
I used a Bosch Colt palm-router as the spindle, and for the control circuitry I used the hobbyCNC kit. Aside from those two components I made it from scratch, using mostly MDF. For the linear movement I used the idea from the buildyourcnc tutorial, which involves aluminum angles and skate-board bearings. Instead of buying expensive bearing blocks, I just took blocks of UHMW-Polyethylene and drilled holes into them that matched the ACME lead size. I bought some anti-backlash ACME nuts from dumpsterCNC, which worked out pretty well (they are mounted to the carriage assemblies using blocks of UHME-PE). I used 205 oz-in (unipolar rating) steppers, but they support a bipolar driver so a future project of mine is to design and build a bipolar driver.
In the video I am just engraving some wood, but I have also used the machine to mill out a better router-mount, which you can see in the video. I also plan to mill better gantry supports (the current ones are waaaay oversized).
Post any comments to the youtube video, since I don't check this site as often. Any advice would be greatly appreciated!!!