Charlie,
The pinhole tends to become obscure after a few holes, but I just blow the debris away with a can of air. The real drawback to this setup is going out of calibration with horizontal movement of the drill head. It's easy to fix, however; just remove the project box lid, replace the shim and drill a new hole.
Baxter
--- In Homebrew_PCBs@yahoogroups.com, Missouri Guy wrote:
>
> Neat idea, but I gotta ask...does the light down below collect any
> dust from the drilling or does a vacuum pretty much
> take care of that.
>
> Charlie
>