Oops, never mind... (I forgot how easy it is to find stuff like that in the
archive!)

I think Susan was answering the wrong question when she said 3.5mils minimum
clearance.
That is the minimum clearance we have been given for COPPER to COPPER, but
we are always
given a different number for DRILL to COPPER.

Every fabricator I have asked has said somewhere between 11 and 15mils drill
to conductor.
If your customer is "bending the rules" then you have to charge for the
reduced yield or else
teach them that just removing inner layer pads doesn't give them the freedom
to route right
up to the holes.

Unfortunately, that is just a rule of thumb I have always remembered, and I
don't remember
ever seeing anything about it in IPC about it. I just tried to look it up
and all I see is conductor
to conductor, sorry

Hope that helps?
Jack

 -----Original Message-----
From:   Olson, Jack
Sent:   Thursday, September 14, 2000 8:58 AM
To:     'Scott A. Bowles'
Cc:     [log in to unmask] ORG (E-mail)
Subject:        RE: PTH clearance/spacing to conductor

I didn't hear the question....
could you repeat it please?
(try to include the quote if you are answering someone)

Jack

 -----Original Message-----
From:   Scott A. Bowles [mailto:[log in to unmask]]
Sent:   Thursday, September 14, 2000 5:15 AM
Subject:        Re: PTH clearance/spacing to conductor

Phil,
Thanks, but I have perused those specifications and did not come up with a
concrete answer.  I was hoping some designers would know if there was a
section that specifically covered my question and/or give me their personal
design criteria.  I am surprised I did not receive more feedback from all
the
designers that usually comment on the TechNet.
Scott

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