DIY AR-15 Build: Pivot Pin Installation

by June 8, 2011 06/8/11
4 of 8 in the series DIY AR-15 Build

Today in part four of our DIY AR-15 Build you’ll learn how to install the Pivot Pin on your Lower Receiver and hopefully take our recommendations on board for a happier stress-free build!

This can either be one of the most complicated steps in assembling a lower receiver, or a relatively easy one. It just depends on your tool selection.

When inserting the detent that holds in the Pivot Pin, it’s quite common for it to turn into a Pegasus Missile and shoot across the room along with the spring that’s under tension. In this article we’ll describe a good method to utilize and mention a tool that will help avoid detent missiles!

Pivot Pin Installation

DIY AR-15 Build - Pivot Pin 03
All Rights Reserved by ITS Tactical One of the reasons we like the Stag Arms Lower Parts Kit is that it comes with one extra detent in case yours takes off into the atmosphere during this assembly. As mentioned this step can be fairly simple depending on tool selection. You can get away with what we use in the video below, which is needle nose pliers, a hex wrench and a small punch.

If you want to avoid frustration, we highly recommend the Brownells Pivot Pin Installation Tool, which is a cylinder that fits into the Pivot Pin ears and has a small cutout for the detent. You simply insert the spring, slide in the tool, put the detent into hole and push a small punch in and turn. This traps the pin without the Pegasus Missile effect. This will of course make more sense when we describe the installation in detail below.

Parts Needed:

Tools Needed:

Assembly Instructions

  • DIY AR-15 Build - Pivot Pin 02
    All Rights Reserved by ITS Tactical Put the lower on the vise block and tilt it towards you to so you can work easier.
  • WARNING: The Pivot Pin Spring and Detent can launch out during this section and if you lose them you’d better have good eyes or you’ll be ordering replacements!
  • Insert the 3/16 Hex Wrench from the port side flush with the outer starboard side pivot pin ear.
  • Insert the Detent Spring into the Detent Spring channel in the lower.
  • Using the needle nose pliers, grasp the detent and push it onto the spring. Once it inserts into the channel, take a small punch and hold it there.
  • Carefully slide the punch away as you maneuver the Hex Key over the spring and detent, capturing them.
  • With the flat cut section of the Pivot Pin facing aft, slide it over as you back the hex key out.
  • You’ll now be able to test the Pivot Pin’s functionality by ensuring it’s capturing the detent as it moves back and forth.

ITS Tactical Logo Lower Receiver

Don’t forget about our exclusive offer to our Plank Owners and Crew Leaders to get a ITS Tactical Logo Lower Receiver from Spike’s Tactical for $99! Click here for more info! Offer ends June 10th!

Join us back here soon for our 5th installment in the DIY AR-15 Build where we’ll be assembling the Trigger Group!

DIY AR-15 Build - Pivot Pin 01DIY AR-15 Build - Pivot Pin 02DIY AR-15 Build - Pivot Pin 03DIY AR-15 Build - Pivot Pin 04DIY AR-15 Build - Pivot Pin 05

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Matt C
Matt C

Hi.  This is really easy.  I inserted the spring.  Then, I got a small pair of tweezers and held the detent from the side above. Carefully push the pivot pin down until it fits through the hole and insert.  ...done.

Matt C
Matt C

Hi.  This is really easy.  I inserted the spring.  Then, I got a small pair of tweezers and held the detent from the side above. Carefully push the pivot pin down until it fits through the hole and insert.  ...done.

Matt
Matt

Why not just use a punch to compress the spring, slide a paperclip in the small hole in the side to hold the spring compressed, drop the detent in, slide the pin through, then remove the paperclip? Is that not possible for some reason?

Brian C.
Brian C.

Great vid. Used the Brownells tool and completed this task in less than 30 seconds. Pushing a punch through the hole in the tool completely alleviates the concern of the detent flying out. Push in, rotate and the detent is trapped. Slide in the pivot pin and you're done.

Tim Curren
Tim Curren

I found the videos to be extremely useful, although I struggled with the front detent pin for quite awhile chasing it around the room before finally getting it installed. This was my first build. I recently built a lower for a friend and used a standard razor blade and needle nose pliers to install it on his. Buy using the pliers toget the pin started and the razor blade to hold it in place the take down pin slides right by the razor blade for quick and painless install. Thanks again for the videos.

Mike
Mike

Great video series. I just order my stripped lower, a stock and the kit and am excited to begin my very first build. I purchased a killer upper at the gun show a couple of weeks ago and am now ready to get this thing rockin. Thanks for taking the time to make these valuable videos. Airborne!

Alan
Alan

So I just completed my first build and it went so smooth, thank you for these videos they came in incredibly handy.... However I think i have found a cure to your detent installation issues. I found holding it in with a thin butter knife did everything i needed it to do, no need for the hex wrench or the multi tool, just man hand the detent in, hold it flush with the butter knife and the takedown pin slides right in no problem....

Allen
Allen

redo the video! lol. spring pops out, cand find it, no one on camera. aannnnddd CUT!

binary options strategy
binary options strategy

Valuable info. Fortunate me I found your site by chance, and I am surprised why this twist of fate didn't took place earlier! I bookmarked it.

AJ
AJ

A handy tip for any build using small springs and pins is to do the work inside of a gallon ziplock bag. That way, when the part launches from your hands, it only travels a coupe of inches before landing inside the bag. Another tip for building ARs (or any guns really) is to put a wrap of electrical tape on the jaws/tip of any tool you use (like pliers/leatherman) so you don't scratch the finish if you slip.

Alex Yuam
Alex Yuam

All I do is put in the spring and the detent in and push it all the way in and put a thin, but sturdy card like a business card and then I push the pivot pin in and pull the card out.

Pudge
Pudge

An 1/4" adjustable clevis pin works great. Any hardware store should have them and they are around a buck.

JM
JM

The Brownells Pivot Pin Install Tool is definitely a must have, but I still had a couple of detent/spring missles fly across my room before finally getting the pivot pin installed. Thanks for doing this series b/c the more people who know how to build a LBR the better.

Josh C.
Josh C.

I use a utility knife blade to hold the spring and detent pin in place while slipping the takedown pin over and into place. This works great if you don't have the install tool, or for some reason have to make the repair in the field. Thanks for the articles!

Josh C

Chattanooga, TN

Josh C.
Josh C.

I use a utility knife blade to hold the spring and detent pin in place while slipping the takedown pin over and into place. This works great if you don't have the install tool, or for some reason have to make the repair in the field. Thanks for the articles! Josh C Chattanooga, TN

Fastlane
Fastlane

The longest part of my build was finding the detent post-launch. It had bounced off three walls clear into the next room.

Bryan Black
Bryan Black

Pudge, interesting on the Clevis Pin. Never even heard of one of those before you brought it up. Might work perfectly if the hole in it is large enough for the spring and detent.

Bryan Black
Bryan Black

Couldn't agree more JM! Thanks for the kind words and support!

Tom F.
Tom F.

After several failed attempts using a punch to capture the detent, I used a 1/16" X 1/4" Popsicle stick to hold the detent while I sipped the pivot pin in. That worked great the first time! This is similar to the utility blade concept described earlier.

Thanks for all the great ideas!

Tom F.
Tom F.

After several failed attempts using a punch to capture the detent, I used a 1/16" X 1/4" Popsicle stick to hold the detent while I sipped the pivot pin in. That worked great the first time! This is similar to the utility blade concept described earlier. Thanks for all the great ideas!

Pudge
Pudge

The holes on a 1/4", fit the detent perfect. Used on my first build and got takedown pin first try and it was truly simple.

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