Ex-USAF & RAAF F-111 engineers.....
 

Hi, the only place I can think of to get some information, the forum has helped with a couple of other inquiries over the years....
A friend gave me this, he was told it was from an RAAF F-111, titanium bolt is 100mm long from the flange, 20mm diameter, (would it be metric if it´s from a US aircraft?).
The thread should be longer if the spring lock on the ´nut´ should contact it so it is probably not for this bolt.
Any help appreciated, even if it is just saying what this type of nut was used for..... looks interesting, cheers, John
https://cimg5.ibsrv.net/gimg/pprune....34e2a62346.jpg

Retired, so no longer in a position to verify, but it looks just like a King Air wing attachment bolt and barrel-nut. The clip on the nut is not a locking device; it's to hold the barrel-nut in place and correct orientation until the bolt mates it. The bore that the barrel-nut sits in is cylindrical, so its important that the bolt is not too long or it will damage the bore.

I say King Air but, of course, other aircraft may use a similar arrangement.

Great information, thanks Duncan!

Seen the same config on engine mounts.

Fairly common on helicopters e.g S76 main gearbox attachment, AW139 Tailboom attachment
This type of nut is designed to spread the bearing load more evenly and with a greater surface area. It has no sharpe edges in the contact area .

Could be this https://www.parttarget.com/5310-01-5...4-0E58F01F4E9C

Nut, wing attachment bar from Lockheed Martin

Looks like it. But;

"Nut, wing attach bar"

is

"Nut, wing attach barrel", but limited to 20 characters/spaces.

Tension bolts (sometimes coupled with barrel nuts), such as you have shown, are not uncommon, and appear in all manner of aircraft as noted. They don't offer the most elegant design for a major joint, but sometimes they are the best compromise.
Most high strength tension bolts employ a 12 point head as depicted here (eg ms21250, bacb30us), so they will all "look the same" at first glance.
Barrel nuts aren't the neatest: you have to torque the bolt not the nut, and they can be a bit fiddly as they reside in a pocket.
Lockheed love them. C130 inboard outboard wing joint, google "c130 Rainbow fitting"
Can't help you on specifics of this one, but there may be some pics out there. DSTO did a heap of work on f111 wing pivot fittings and carry through structure, try googling that, who knows what youll find. F111 taught damage tolerance analysis to several generations of engineers in Oz.