Re: gEDA-user: Correct drill size for pga pins

[Stephen Trier <stephen.trier+geda@xxxxxxxxx>]

   Oliver,

   I've used the chart from this Mentor app note:

   [1]http://www.mentor.com/resources/appnotes/upload/through-hole-padstac
   ks.pdf

   The terminology is a little different, but basically it recommends that
   for your 0.5 mm hole, you should have an 0.7 mm finished hole size
   (that's the "drill" parameter in PCB's pin definition, assuming your
   PCB house accepts finished hole sizes -- most do), a 1.2 mm
   "thickness", a 1.2 mm "mask", and an 0.3 mm "clearance". The last comes
   from the 1.5 mm "plane anti-pad" Mentor recommends minus the 1.2 mm
   thickness.

   Sometimes I want to tweak these numbers for a particular purpose, in
   particular to make the thickness and mask a bit bigger for hand
   soldering or just the mask bigger if I have doubts about the PCB
   house's registration abilities, but the app note numbers make a decent
   starting point.

           Stephen

References

   1. http://www.mentor.com/resources/appnotes/upload/through-hole-padstacks.pdf


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