Re: 34 pin Card Edge “Male to Male” Connector

[Eric Smith]

On Wed, Nov 28, 2018 at 7:05 PM Chuck Guzis via cctalk <
cctalk at classiccmp.org> wrote:

> > 2) is there some way to specify "hardened" or whatever plating for the
> connector traces?
> My last order from OSHPark came with all traces gold-plated.
> Apparently, it's getting to be standard practice.
>

Sure, but that's just 0.05 to 0.125 microns of ENIG (electroless nickel
immersion gold). That's not intended for mating surfaces, and will wear
away after only a small number of connector cycles.

For reliable edge fingers you need "hard gold" (AKA "hard electrolytic
gold"), which is 0.75 to 2 microns of gold electroplated over 3 to 6
microns of nickel.

(Be careful out there, a lot of places still specify the nickel and gold
thickness in microinches.)