Homebrew PCBs

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.

Thanks,

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of bebx2000
Sent: Tuesday, January 01, 2013 9:55 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: circuit board drilling question






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