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Silver coating on internal threads of nut only, not on its hex surface

WE ARE MANUFACTURERS OF DOUBLE FERRULE COMPRESSION FITTIGS & WOULD LIKE TO KNOW WHETHER THERE IS ANY PROCESS OF COATING ONLY THE INTERNAL THREADS OF NUTS & NOT ITS HEX SURFACE.IF THE HEX SURFACE OF NUTS GETS COATED WITH SILVER THE FINISH OBTAINED IS QUITE IN CONTRAST WITH THE HEX SURFACE OF THE BODY.THEREFORE I NEED TO KNOW THERE IS ANY PROCESS TO COAT ONLY THE INTERNAL THREADS OF THE NUT.

SUDHANSHU DIGHE
FLUID CONTROLS - MUMBAI, MAHARASHTRA, INDIA
2005

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Indeed there are shops who specialize in just this. Sudhanshu. I'm pretty sure the only way to do it is to mask the external surfaces, plate them, and then remove the maskant.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005

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First of two simultaneous responses --

Adding to Ted's advise maybe you can tap and plate an hexagonal bar before cutting the nuts out of it. The bar being as long as the plating eqipment and process permits with acceptable deposit thickness and quality. You could save masking material and time.

Guillermo Marrufo
Monterrey, NL, Mexico
2005

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Second of two simultaneous responses -- 2005

What size are the nuts?
Masking and demasking are very time consuming and a bit of money for the maskant.
Plating the whole thing and blasting the external surface is also time consuming and wastes silver.
There is no other way for tiny or small nuts that I know of.

James Watts
- Navarre, Florida

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