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From: karl AT aspodata DOT se
To: geda-user AT delorie DOT com
Subject: Re: [geda-user] pin drill and thickness statistics from cvs.gedasymbols.org
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   message dated "Sun, 14 Jan 2018 21:26:23 +0100."
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Precedence: bulk

Do theese thickness diameters look reasonable ?

 all values in mm
 c  = small/tight
 b  = hopefully something normal
 a  = something somewhat big
 aa = big thickness

hole      c     b     a    aa
  0.3   0.8   1.0   1.2   2.5
  0.4   0.9   1.1   1.3   2.7
  0.5   1.0   1.3   1.5   2.9
  0.6   1.1   1.4   1.6   3.0
  0.7   1.2   1.5   1.8   3.2
  0.8   1.3   1.7   2.0   3.4
  0.9   1.4   1.8   2.1   3.5
  1.0   1.5   1.9   2.3   3.7
  1.1   1.6   2.1   2.4   3.9
  1.2   1.7   2.2   2.6   4.1
  1.3   1.8   2.3   2.7   4.2
  1.4   1.9   2.4   2.9   4.4
  1.5   2.0   2.6   3.0   4.6
  1.6   2.1   2.7   3.2   4.7
  1.7   2.2   2.8   3.4   4.9
  1.8   2.3   3.0   3.5   5.1
  1.9   2.4   3.1   3.7   5.3
  2.0   2.5   3.2   3.8   5.4
  2.1   2.6   3.4   4.0   5.6
  2.2   2.7   3.5   4.1   5.8
  2.3   2.8   3.6   4.3   5.9
  2.4   2.9   3.8   4.4   6.1
  2.5   3.0   3.9   4.6   6.3
  2.6   3.1   4.0   4.8   6.5
  2.7   3.2   4.2   4.9   6.6
  2.8   3.3   4.3   5.1   6.8
  2.9   3.4   4.4   5.2   7.0
  3.0   3.5   4.6   5.4   7.1
  3.1   3.6   4.7   5.5   7.3
  3.2   3.7   4.8   5.7   7.5
  3.3   3.8   5.0   5.8   7.7

each column is
  thickness = a0 + a1 * hole_dia

        a0      a1
c:   0.2662  1.0966
b:   0.6041  1.3211
a:   2.0090  1.7107
aa:  0.7195  1.5476

I got theese by the procedure outlined in

 http://aspodata.se/git/openhw/share/pcb/data_from_cvs.gedasymbols.org/readme.txt

///

Loocking at https://www.samtec.com/support/pcb-hole-sizes I get much
tighter values: 0.130 1.011

///

Does IPC have any recommendation about this ?

Regards,
/Karl Hammar

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