In my relatively limited experience, one of the key factors is how precisely you can drill. My most recent board has .045 diameter via pads, drilled with a .6mm drill (0.024"). Even though I managed to get the registration between the top and bottom more or less perfect as far as the toner transfer and etch, I discovered that it was easy to drill the holes at an angle, at least using HSS drill bits. The drill is so small that it bends very easily; you can be off-center just a bit; the bit goes in right (because of the little etched dimple created by my software), but it comes out in the wrong place.
Obviously, I need to work on my drilling, both equipment and technique!
--- In Homebrew_PCBs@yahoogroups.com, Chris Maness <chris@...> wrote:
>
> What is the minimum pad size (in mils) for home made PC boards? (Single
> Sided).
>
> Thanks,
> Chris Maness
>
>
> [Non-text portions of this message have been removed]
>