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Galling between silver plate and nickel plate threads

We are a manufacturer of electronic interface devices for the military, using rf connectors built to MIL-SPEC M39012 and earlier. We have a problem that looks like it may be gauling. The female connector is nickel plate over brass. The male connector is silver plate over brass. Both parts are supposed to be built to the same spec and mate together, but tey don't. It could be coincidental that silver will mate with silver, but not with nickel in the units that we have built so far, but if there is another reason, I'd like to find it. I'm not a finishing guy, just an electronics hardware designer trying to spend the taxpayers money wisely. I've read several of the ongoing issues and discussions here. I'm sure someone can help. Thanks in advance:)

Chip Brown
- MILCOM Systems Corp.
1998

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On you question, I fail to understand exactly what you mean by "they don't mate". If the threads are matching and the coating thickness is in spec, they should fit the first time but may freeze with repeated use due to galling. But silver is supposed to provide lubrication. If the coating(s) are too thick, then mating would be a problem. In the case of galling, the coatings will weld to each other and will appear smeared, not just deformed.

Mandar Sunthankar
- Fort Collins, Colorado
1998