Last night I downloaded CADsoft Eagle schematic drawing and PCB design software. Learned just enough to make a basic board. Used an Eagle to Gcode converter and created the gcode.
Tie-wrapped a rollerball pen in place of my router, added a flat (MDF) auxiliary table on the Router base, got the paper flat.
Started the EMC software, opened the gcode file. It looked perfect with a "rats nest" of jogs. I set X and Y to home, set the touchoff, and hit 'go'. Board is about 2.5 by 2.0 inches.
Son-uv-a-gun. It did pretty damn good. I am pretty sure I had some of the feed rates too high, and I think I skipped a step or two. Nevertheless, I was blown away. It takes a L O N G time to route. One key learning: keep as much copper on the PCB as you can!
Here is a close-of the bottom left of the PCB. The holes are marked quite well in the pad centers. This was not the case everywhere, though. Next time, I will slow down the steppers.
This will make prototyping PCBs fun, clean and fast (faster than the chemical options!).
I will document my complete setup and experience.
Here is a 73 second video of the CNC machine drawing with the roller-ball pen. You can see the pen flex and the paper move - these are, no doubt, large contributors to the inaccuracy.