This happens to be a front pivot pin for a Colt AR-15 rifle. It is an ‘inside out bolt’. That is, the threads are on the inside of a smooth cylinder. It has a screw head at one end, and another screw screws into the interior threads. I’ve seen similar things for notebooks/binding punched paper.
What is the proper name for this piece of hardware?
I think it’s called a binding barrel.
Sex bolts is a funny name. The link says they’re also called Chicago bolts.
Thanks, guys!
Yep, Chicago Screws. Used many when putting photo albums together.
My ARs use pins that just slide in. Don’t have any Colts though.
There’s a website called Bolt Depot? I think I just died and went to heaven.
Are you sure that’s not a gay bar in West Hollywood?
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They are also apparently called architectural bolts. So pick your favorite…
binding barrel/post/bolt
sex bolt
Chicage bolt
architectural bolt
they should be called a barrel nut.
That’s the name I’ve heard.
“Sex bolt” is the only term I’ve seen for this.
Are you sure it’s not a self-sealing stem bolt? 
Barrel nut and sex bolt are the two terms I’ve seen used.
I’m going to Home Depot tomorrow and demanding they sell me the sex bolts, ALL the sex bolts.
They are also also called screw posts. Just saying.
When I was introduced to them, we called them Jailhouse bolts, as the type we used were supposedly only one way.
They are used to put the stall around the toilet together in public restrooms.
People will steal anything!
Barrel nuts or screw posts but from now on sex bolts!
Band name!!
You’re onto something there.
