Rick,
I think you misinterpreted the arrangement. The drilling is down from the top, but the light is shining up through the bottom of the board. The board is placed on top of the project box which has the laser pinhole setup. I use the Eagle drill-aid.ulp which provides a smaller etched hole than the regular hole. The board is positioned (looking down on the board) so that when light appears in a hole that is where the drill will penetrate. This has improved my depth perception so that now I can pretty much drill a straight line of holes.
Baxter
--- In Homebrew_PCBs@yahoogroups.com, "Rick Sparber" <rgsparber@...> wrote:
>
> Baxter,
>
> Our approaches are rather different. I'm hoping to shine light through the
> board so the pad feature is clearly outlined. I figure that would be more
> precise and clearer than shining lights down on the board from above and
> seeing the reflected light. From above I would be unable to shine straight
> down so would get shadows. From below I can shine straight up. Hope to have
> this mod tested today.