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Screw threads will not accept Go gage after chrome plating

I work for a distribution company that supplies Chrome Plated fasteners to the Automotive and Motorcycle markets. The parts are stripped in a pickle & oil process prior to plate. The chrome plate applied is a decorative chrome per ASTM B456, class SC1. Our issue is that the parts will not accept a thread ring gage after plate. The screws are a class 3A fit proir to plate, and that leaves very little tolerance to accept plate and still gage.

Our question is, are there plating racks that will limit the amount of chrome on the threads, yet plate more chrome on the head of the screw to provide corrosion protection?

Brian Smith
Product Manager - Troy, Michigan, USA
February 10, 2010

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It is possible, but it is almost certainly not cost effective to engineer and fixture in a current robber for the plating of screws. A more likely scenario would be to either mask the threads completely so that no plating is performed on the threads or to make allowance in the machining of the part to achieve the appropriate dimension after plating.

Jon Barrows, MSF, EHSSC
GOAD Company

Independence, Missouri

February 12, 2010

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February 14, 2010

Hello,

it must be together with the customer investigated, either the Specification they do like to have doesn't really fit on the design of the thread. Either way, I do rather recommend using shield techniques to avoid an excessive plating amount on thread as masking all the threads (depends on production amount => high labour and material costs).

Regards,

Dominik Michalek
- Sydney, Australia