I use a laser pointer mounted horizontally in a project box. The beam is directed to a 45 deg. mirror to turn the beam upward through a hole in the top of the box. A brass shim is affixed to the inside of the box covering the hole. The calibration is done by taking the finest drill bit you have and drilling a hole in the brass shim. This assumes that you have pretty much aligned everything and fixed the box to the drill table before drilling the hole. After drilling don't move the drill head horizontally. The spot of light shining through the PCB is exactly where the drill will penetrate. There is some diffusion of the beam, but it doesn't seem to matter. Adjust the vertical depth of the drill head movement so you don't mess up the brass shim pinhole. I suppose this might also work with an LED.
Baxter
--- In Homebrew_PCBs@yahoogroups.com, "Rick Sparber" <rgsparber@...> wrote:
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> Has anyone played with putting a high intensity LED pointing up through the
> drill press table so it would be easier to see the circuit board land before
> drilling?
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> Rick
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