rlspell2000 pravi:
> I used to use a drill press, but the two sides are occasionally mis-aligned.
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> I went to free hand dremel drilling so I could hold it at a slight angle and hit the center of the pad on the opposite side. I etch the hole in the center of the pads out so the copper guides the bit into the center.
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> Then one day I had an idea. (hey, it could happen).
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> I now drill about 1/2 way through from one side freehand, flip the board over, and drill the rest of the way through from the other side. The tiny bit tends to hit the hole that has already been drilled and self-center. Only rarely do I have a through hole that is not exactly in the center on both sides now.
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Carbide drill can easy break if you point it in same hole twice. At
least 0.8mm in dia (32 mils)