Tip: NAS1097 is MORE than an "oops"

[Rick6a]

Labeling a NAS1097 rivet as an "oops" rivet may be a convenient soundbite directed at the amateur builder trying to fill a wallowed out hole but like all soundbites the folksy little term "oops" also serves to undermine the true value of this type rivet. The NAS1097 is available in diameters at least up to AD6 (that I am aware of) and has been used in aerospace production work for a long, long time. By far, it is most commonly used for routine nutplate attachment. Why Van's has never encouraged this useful application has always been something of a mystery to me. You can easily 100° countersink thin .025 material without risk of generating the dreaded "knife edge." Seems to me that altering a nutplate with dimples is crude compared to simply using a NAS1097AD3 in the first place. The images below are only partial examples of situations where I found the NAS1097AD3 to be a useful, even desirable alternative to machining a standard size countersink.

[SMO]

I have used hundreds of these AD3 rivets in my F1 including all the nutplates. I don't recall having used one for an "oops" (which is not to say I haven't had any "oops" events!). The beauty of these little guys is that it only takes about 8 spins of my deburring tool to create the countersink for them. Very quick and easy.

[Rick of Austin]

Rick, I was also curious why Vans wants us to dimple nutplates and use standard 426 rivets in hundred of places on the -12? I am just now becoming familiar with the -12 design details by reading all the SBs and thats the first time that technique has ever been described.
Could it be that there is less chance of damage the skin due to over countersinking? Or maybe its the .020 skins that require this.
It seems crude to me as well to dimple nutplates, but since I intend to build a -12 and would like the option to register it as experimental so I have to be careful of making too many changes. Any suggestions?

[GAHco]

Old Info is still Good News to those who have not heard it.
Thanks for posting the benefits, previous listers.

I have been selling these for over 20 years, and they work as intended. Sometimes these Reduced Head Countersunk rivets work well for things that they were not intended for, and that is what puts us in the experimental zone.

We stock 56 different NAS1097 items#'s

This is the smallest 3/32 rivet we sell http://www.gen-aircraft-hardware.com...097AD3%2D2%2E5

We also have a fair amount up to 1/4" diameter.

I use this type on my RV6 for nutplates 3/32, and for Oops 1/8th dia.

[Patch]

I am familiar with Certified aircraft using both the NAS1097AD3 and the NASM20426AD3 rivets for platenut applications. They generally call out the 426 rivet in locations where the platenut would be hard to get to for replacement. I have seen 1097s torn out by a heavy handed mechanic when installing the bolt. The larger head is more tolerant of this type of treatment. This is also why it takes an act of god to get design approval to allow a single lug platenut, because when they get bent over then the bolt will not install requiring replacement.

Long winded but Vans is probably thinking smaller head pulling through thinner material could be potential future problem.

[tomcostanza]

Why Van's has never encouraged this useful application has always been something of a mystery to me.

They don't encourage it, but they do mention it as one of the ways to mount a nutplate (section 5R). I guess, since they don't sell these rivets, you might say they discourage using them. I tried both techniques, and there's no comparison. The NAS rivets are the absolute winners.

[sprucemoose]

Van's does sell 1097 rivets, at least they used to.

[llavalle]

See my post about the exact same tip posted last year :

http://www.vansairforce.com/communit...ad.php?t=41352

[Greg Arehart]

Wish I had known this when I was doing nutplates in thin stuff..... guess I should have read the manual more carefully....

Good tip!

greg