Homebrew PCBs

I use Eagle for my boards. I have written/modified a User Program (sort of
an interpreted C language built into Eagle) that outputs HPGL plot files
specifically for my use. I don't use a mill, I use an HP plotter with a
scratching tip instead of a pen. I put paint on my copper boards, then run
them through the plotter. The plotter 'scratches' away all of the paint
where I want the etchant to etch.

I have a program that I wrote (in Liberty Basic) that takes the HPGL output
from Eagle, and the NC Drill file from Eagle, and puts filled in circles
inside each drill hole. Then when I scratch the board on the plotter, each
drill hole has a copper-free circle in the middle of it.

None of the stuff I've done is ready for any type of wide-spread use yet.
I'm still working out lots of bugs. But I'm writing this to you-all so that
you know it can be done, and it isn't all that hard to do. My Liberty Basic
program parses the HPGL file from Eagle (which contains many concentric
'rings' of scratch lines since each scratch line is only about 2-4 mil wide)
so that areas can be 'filled-in' with scratch lines) and then parses the
drill file and combines them, does rotates, scaling, and translation, and
then writes out a new HPGL file that I can directly use on my plotter.

*Brian