Re: gEDA-user: [pcb] drill helper

[phil@plastitar.com]

Having spent a previous life as a die maker, I know that drills like to
find a low spot to center themselves on.  When machinists need a hole in a
precise location they use a smaller, very stout drill to make a starter
hole.  I concur that a (15 thou.???)  starter hole for hand-drilled PCBs
will aid in ctc accuracy.  There is probably a way to compute from drill
diameter, copper thickness and lead angle exactly the best diameter
starter hole for a particular diameter of drill.  Say the diameter of hole
that allows the drill to contact copper before the substrate by a few
mils?

Phil Taylor



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