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Self tapping screws through hard anodize

I would like to find out if it is possible or practical to hard anodize a piece of 3/16 6061 aluminum and then use a self tapping or thread cutting screw to create a ground? Will I be able to make enough contact on a 4-40 screw assuming the anodize will be 1.5-2 mils. I need to be able run at least 25 amps on a default mode through the ground. Has anyone had any experience doing this? I could use some help.

Thanks,

Dan St. John
- Tualatin, Oregon
2002

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First of two simultaneous responses

My suggestion would be to drill a hole but don't tap it. Have the anodizer plug the hole (cheap) and then use your self-tapping screw to establish the ground. Tapping into aluminum oxide is tough, will be hard to align straight and likely to give inconsistent results.

Milt Stevenson, Jr.
Syracuse, New York
2002

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Second of two simultaneous responses

A 6x32 might make it, but I would expect grief with a 4x40. A thought, why not use a silicon pull plug to mask the hole. Easy in, easy out. Tygon tubing can also be used with a little more difficulty but a lot less material cost. The silicon plugs are reusable for several times. Several vendors at this site.

James Watts
- Navarre, Florida
2002