Reduced Head "oops" Rivets

Hi All,

I've searched reference manuals and online forums, but I can't locate info on the use of reduced head (oops) rivets. It's been a while, but I vaguely remember regs (?) guidelines (?) rule-of-thumb (?) as to:

1- limits on how many reduced head rivets can follow one-another in order,
2- how many reduced head rivets can be used in a specific row.

Can anyone provide specific reference (manual, AC, etc.) or are guidelines purely "tribal knowledge"?

The often maligned NAS 1097

I look forward to what follows on this thread.

Reduced head rivets have their own rightful place in aircraft. So I don't act like an authority I'll quote from: A New Generation, The evolution of aircraft rivets by RONALD STERKENBURG

"The NAS 1097 100-degree reduced head countersunk rivet is similar in design to a regular countersunk rivet, but the head is reduced so that it can be installed in thinner sheet material. This rivet is used in many modern airliners."

EJWash said:

Hi All,

I've searched reference manuals and online forums, but I can't locate info on the use of reduced head (oops) rivets. It's been a while, but I vaguely remember regs (?) guidelines (?) rule-of-thumb (?) as to:

1- limits on how many reduced head rivets can follow one-another in order,
2- how many reduced head rivets can be used in a specific row.

Can anyone provide specific reference (manual, AC, etc.) or are guidelines purely "tribal knowledge"?

Click to expand...

Short answer = As many as you need though someone will probably flame on this. A rivet's purpose is to provide counter shear force in bearing. That is done via the swelled shank. The manufactured head is just along for the ride if applied properly. NAS1097 rivets have a shank that is one "size" larger. If you have proper edge distance and pitch minimum (spacing), no longer think twice about it.

Many certified manufacturers utilize 1097s to a surprisingly great degree. IIRC Pipe Saratoga wings, some Lear Jet wings are almost all assembled with 1097s. I'm sure there's more and VAF world will jump in it my memory is off.

Sounds like you're already using 1097s. Consider getting a stash of 1241s which are 1/64" oversized. You can buy them by the ounce from Flyboys. Get long ones and cut them as needed. That way you'll always have a quick remedy available as long as the aforementioned requirements are met. Would be rare if they weren't as you only need 1/128" and 1/64" "extra" ED etc.

Best of luck

Edit = @wawrzynskivp. Yep, this one could get intersting and passionate. Probably some good insight from fixnflyguy could be forthcoming.