History of the castle nut?

[Barms 98]

Somebody on here has to know why on earth whomever the engineer designing the first AR thought to himself.. "hey.. how about some convoluted ring that can only be turned with a custom made wrench..:"

 

I mean c'mon.  why not just a simple nut that any pair of channel locks can use?

 

Is there some military or tactical origin for this?  Or just to drive me crazy as i consider my first LPK build?

 

do military guys carry that wrench with them in the field?  I don't mean to insult the awesomeness of the design.. its just mind boggling..  maybe there's some science that i don't know about that keeping the ring round keeps it tight?   It can't be so it doesnt snag on something because its common practice to have a sling mount there.   What can it be?

[henrym 19]

Once torqued to the proper spec and staked, one would not need to carry the wrench because it should not move.

[JT Custom Guns 960]

The design was originally introduced by the Castle Nut Wrench Co.

They were looking for an avenue to improve business, and this seemed

to be the logical direction to move forward............

[5th4x4 0]

The design was originally introduced by the Castle Nut Wrench Co.

They were looking for an avenue to improve business, and this seemed

to be the logical direction to move forward............

I believe that's the same company that manufactured the left-handed smoke bender.

Very innovative company.

[JT Custom Guns 960]

Correct!

[5th4x4 0]

Is there some military or tactical origin for this?  Or just to drive me crazy as i consider my first LPK build?

It's use is actually mechanical. Vehicles have them as well. It's a nut that is used when torquing is required.

So no.... it's not a conspiracy to disrupt your build ; )

[5th4x4 0]

 

do military guys carry that wrench with them in the field?  

No way.  No punch sets either ; )

If we can't take it apart with our hands, then we're not meant to mess with it.

 

The armory guys obviously have everything... but they aren't like medics. They don't go running out onto the battlefield when a weapon goes down ; )

[GRIZ 3,369]

Using a castle nut or other special fastener on a firearm is not a new idea. A M1 carbine requires a special wrench to remove the gas piston. Other weapons also require special tools. As henrym said once its in and staked there is no reason to fool with it. That's the reason for special tools.

 

Have used M16s, ARs, and M4s in the military and as a LEO since 1968. Never carried a wrench around. The company armorer would have one.

[Barms 98]

Ahhhh. The torque thing. Well there you have it.

[Vlad G 345]

Err it has nothing to do with torque exactly, it has to do with a need for the tube to stay where it is. The standard rifle setup doesn't have it, because the tube can't move or unscrew as the stock mechanically locks it into place. On the carbine/m4 recoil system there is nothing holding it from spinning, hence a torqued down castle nut.

 

Which in my opinion is dumb as hell, and a expedient hack, because some form of mechanical interference locking mechanism wouldn't have been hard to figure out.

[High Exposure 5,682]

The original Receiver Extension Locking Nut for carbines equipped with collapsable stocks as we know them wasn't "castle" shaped at all.

 

 

That's it there on the left on a Colt 609 CAR-15 (better known as a Cotl XM177 Commando the first AR carbine with a collapsable stock as we know them today)

 

Using a castle nut or other special fastener on a firearm is not a new idea. A M1 carbine requires a special wrench to remove the gas piston. Other weapons also require special tools. As henrym said once its in and staked there is no reason to fool with it. That's the reason for special tools.

Have used M16s, ARs, and M4s in the military and as a LEO since 1968. Never carried a wrench around. The company armorer would have one.

Not all Rifles are built to the TDP and I can't tell you how many are not staked from the factory or were not re-staked after having a sling plate installed by a WECSOG Graduate. Because of this I carry a Multitasker (Multitool designed for use with ARs) at work and especially at the range. The Multitasker has a Receiver Extension Nut Wrench as one of its "blades" that gets a lot more use than I would like.

[alec.mc 180]

anybody else start thinking this automatically ?

 

 

 

on cars, again - for torque - and the cotter pin prevented it from backing out and loosening. 

[5th4x4 0]

anybody else start thinking this automatically ?

 

 

 

on cars, again - for torque - and the cotter pin prevented it from backing out and loosening. 

 

When you consider that it would only be another mechanic who would ever really see that ball joint (if at all).... that is one stylish looking cotter pin configuration : P 

[alec.mc 180]

When you consider that it would only be another mechanic who would ever really see that ball joint (if at all).... that is one stylish looking cotter pin configuration : P 

 

 

lol , i've always done one left and one right, but i suppuse that way will work too

[AverageJoe 95]

This might be a dumb question but why can't it have two flat edges opposite each other? Does it need to be perfectly round? Thinking back, when I swapped out the stock...whoever assembled mine at Bushmaster must of had an extra helping of spinach cause that shit was on gorilla tight...even snapped a nub off my wrench. Ended up having to use a buddy's wrench with a pipe on the end for leverage. Anywho...two flat edges and an open end wrench would of been easier I think lol.

[Vlad G 345]

The problem with flat sides is that may never end up lined up "pretty" and OCD people would freak.

 

A much simpler solution would have been a retainer plate with a hole where the nub is and having the nut be able to screw into the retaining plate somehow after it has been tighten, through the plate into the receiver dimple

[5th4x4 0]

This might be a dumb question but why can't it have two flat edges opposite each other? Does it need to be perfectly round? Thinking back, when I swapped out the stock...whoever assembled mine at Bushmaster must of had an extra helping of spinach cause that shit was on gorilla tight...even snapped a nub off my wrench. Ended up having to use a buddy's wrench with a pipe on the end for leverage. Anywho...two flat edges and an open end wrench would of been easier I think lol.

 

The only reason I can assume that it wouldn't have flat edges, would be to prevent the nut from compressing. It's not thick - and even though it's reinforced internally by the extension - a leveraged wrench could (possibly) flatten-out/distort the shape. (???)

 

The grooves (castle shape) on the outside distributes all of the torque of the wrench equally from the end. No pressure applied on the face.

 

That's a total guess on my part, so I'd also be curious to know if there is a specific designed purpose for that configuration. 

[Barms 98]

Great stuff. But remember the question wasn't what is the purpose of the nut, duh it's to hold the tube in place, the question was why a "castle" nut. I like the torque answer. And of course the OCD look answer.

 

And maybe all else equal the ability to torque down a castle nut weighs less than torquing down a traditional nut? I dunno

[JackDaWack 2,895]

It's a matter of mechanical design. A light yet sturdy option. If you want a standard nut design u either sacrifice weight and space or strength.

[High Exposure 5,682]

If you used "flat sides" the whole nut would have had to have been much thicker in order for the "flats" to still be "meaty" enough to do the job.

[MidwestPX 172]

This might be a dumb question but why can't it have two flat edges opposite each other? Does it need to be perfectly round? Thinking back, when I swapped out the stock...whoever assembled mine at Bushmaster must of had an extra helping of spinach cause that shit was on gorilla tight...even snapped a nub off my wrench. Ended up having to use a buddy's wrench with a pipe on the end for leverage. Anywho...two flat edges and an open end wrench would of been easier I think lol.

I believe BM uses Loctite or some other type of adhesive on their rifles.  The .308 ORC that we re-worked for a SWAT team had the castle nut on that was very difficult to remove and I believe it was due to an adhesive as it was not staked.  

[Shawnmoore81 623]

[Golf battery 1,223]

is this guy a freakin castle nut or what. My kids get a kick out of the hair. Mr heatmiser.

[RUTGERS95 891]

The original Receiver Extension Locking Nut for carbines equipped with collapsable stocks as we know them wasn't "castle" shaped at all.

 

 

That's it there on the left on a Colt 609 CAR-15 (better known as a Cotl XM177 Commando the first AR carbine with a collapsable stock as we know them today)

 

Not all Rifles are built to the TDP and I can't tell you how many are not staked from the factory or were not re-staked after having a sling plate installed by a WECSOG Graduate. Because of this I carry a Multitasker (Multitool designed for use with ARs) at work and especially at the range. The Multitasker has a Receiver Extension Nut Wrench as one of its "blades" that gets a lot more use than I would like.

great looking tool..which model and where can I get one?

[RUTGERS95 891]

check that, found it....

[High Exposure 5,682]

For anyone else interested you can get them at Brownell's.

[Shawnmoore81 623]

I think gerber makes one too. Not sure on the quality though

 

 

Sent from my iPad using Tapatalk HD

[5th4x4 0]

That sure is a mighty expensive gizmo.

 

Check out the Leatherman line. Less pricey, more tools.

[High Exposure 5,682]

If you want to support a company whose CEO is by all reports rabidly anti-2A then by all means, buy a Leatherman.

 

Also having used the Leatherman MUT and the Multituasker, I found the Multitasker a much better tool.

[blksheep 466]

I have the Gerber 600ST...Its a solid tool. Doesnt have the wrench which is fine. I wanted it more for the sight tool built right into it. I was tired of using paper clips and rounds.