identifying aircraft quality

[prkaye]

How do you know if rivets (say ones you found on the street) are "aircraft quality"? If you see a universal head rivet and it has that dimple on the head, does that identify it as an aircraft-quality rivet?

[Stephen Lindberg]

Rivets are so cheap it doesn't make any sense to buy them from other than a reputable supplier. When I buy from Spencer Aircraft (great service) all their hardware comes with a lot number for traceability purposes. Vans doesn't do that but I trust they aren't stocking no-name untraceable hardware. Treaceability doesn't legally affect us as homebuilders but I believe it is mandatory for the military and airlines. I am told that counterfeit aircraft hardware is a problem, also counterfeit aircraft parts, too. Incidently, I would recommend against buying pharmaceuticals on the internet. Same deal. (The dimple indicates the rivet is made of 2117 aluminum alloy, an "AD" rivet.)

[jarhead]

Originally Posted by Stephen Lindberg

Rivets are so cheap it doesn't make any sense to buy them from other than a reputable supplier.

Bingo.

Treaceability doesn't legally affect us as homebuilders but I believe it is mandatory for the military and airlines. I am told that counterfeit aircraft hardware is a problem, also counterfeit aircraft parts, too.

Traceability (of hardware and parts) is an FAA requirement for ALL commercial operations and certificated repair stations. It certainly won't hurt you as a homebuilder...

Counterfeit aircraft parts and hardware is a HUGE problem - the Feds say it's a multi-BILLION dollar industry. They call it "SUP" - Suspected Unapproved Parts. The program's focus is aimed more toward counterfeit parts than hardware, but hardware is a problem too. Not just in aviation, either - apparently there's a huge amount of "Grade 8" hardware (the strongest "hardware-store" hardware) out there that isn't...

[gmcjetpilot]

Originally Posted by prkaye

How do you know if rivets (say ones you found on the street) are "aircraft quality"? If you see a universal head rivet and it has that dimple on the head, does that identify it as an aircraft-quality rivet?

The dimple means it is a AD rivet or 2117T rivet. Here is a nice picture:

http://www.engineersedge.com/hardwar...act_rivets.htm


Its more likely you will run into low quality blind or pop rivets, but that is a different story. There is aircraft quality pop rivets often under the trade name Cherry Max. Identification of high quality "blind fasteners" and plan "pop rivets" by just looking at them after installed is a little more difficult, unless you have a trained eye.

For solid rivets you can see a 1100 rivet has less strength. So you want to assure that you use the rivet specified by the designer.

An interesting note, referring to the chart above some rivets are heat treated before using, other wise they would be too hard to drive. After heat treated to a soft condition they're stored frozen. These rivets are the so called "ice box rivets". Freezing keeps them from age hardening. Once you drive the rivet it "work hardens" and regains its strength. None of this applies to the rivets we use, so forget about it.

Keep in mind a stronger rivet in thin sheet metal does not increase the strength of the structure; the sheet metal is likely the weak link. The stronger rivets are for heavy aircraft with thicker structure.