CBM edge connectors pitch?

[Eric Smith]

On Thu, Oct 13, 2016 at 1:56 PM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
> As Tony suggests, it matches up with 5/32" spacing, just as 0.125 is 1/8".
> Where the rounding of the 1/4 thou (0.00025) took place - in the name or the implementation - I'm not sure.

Implementation.  Years ago I verified with several vendors that the
connectors really were engineered for 0.156" or 3.96mm, not 5/32" or
3.97mm.  (I'm not 100% certain that was always true, but it was when I
inquired.)

It doesn't make much difference in practice.  The highest pin-count
.156" connector I've ever dealt with was 86 pin (43x2), and the
difference in the nominal first-to-last position is only 10.5 mils,
which is on the order of the non-cumulative position tolerance.

I just happened to look at the drawing for a TE 2-530666-1 connector,
and they specified the pitch in one place as 0.156/3.96 (in/mm), and
in another place in the same drawing as 0.156/3.175.  Oops!