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Posted: 5/1/2021 12:43:17 PM EDT
[Last Edit: 5/1/2021 12:44:13 PM EDT by Holdemdown]
Anybody have a source for real roll pins(like a fruit rollup)  not these god awful split C pins?

ETA- dont say mcmaster carr, dont need 100.
Link Posted: 5/1/2021 2:56:43 PM EDT
[Last Edit: 5/1/2021 4:48:16 PM EDT by Tigwelder1971]
Check your local hardware store.


Otherwise,  THIS will work.  

Edit:  Borked.
Link Posted: 5/1/2021 4:18:18 PM EDT
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Originally Posted By Tigwelder1971:
Check your local hardware store.


Otherwise,  THIS will work.  
View Quote

Ammunition forum?
Link Posted: 5/1/2021 4:46:11 PM EDT
[Last Edit: 5/1/2021 5:10:55 PM EDT by Tigwelder1971]
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Originally Posted By Holdemdown:

Ammunition forum?
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Holdemdown:
Originally Posted By Tigwelder1971:
Check your local hardware store.


Otherwise,  THIS will work.  

Ammunition forum?

Well , that went fuckey.

THIS was what I was after.
Link Posted: 5/2/2021 4:50:49 PM EDT
Originally Posted By Holdemdown:
Anybody have a source for real roll pins(like a fruit rollup)  not these god awful split C pins?

ETA- dont say mcmaster carr, dont need 100.
View Quote

You’re talking about “coil pins,” rather than “real roll pins”?
THIS:    NOT THIS:
Images from McMaster-Carr’s pages for these products.

McMaster-Carr makes it easy to differentiate the two types.  “Slotted spring pins” are what everybody thinks of as “roll pins,” and these are what the AR platform was designed to use.  These pins deform as you install them, then hold themselves firmly in place - which makes them a little harder to remove and replace.

The other type is called “Coiled spring pins.”  Their virtue is that they remain flexible once installed.  Which means, while they’re somewhat easier to install and remove, they don’t stay as firmly in place in AR applications.

I’ve had a little experience with coiled spring pins, and I wasn’t impressed.  Supposedly these let you install trigger guards without as much risk to the receiver’s ears.  They also don’t work as well with roll pin punches, and the one I’m thinking of wanted to expand out the end from the inside while I was installing it.  F-that.  I got the specified roll pin, used a nifty little screw clamp tool to install it, and that pin hasn’t moved a micron since.
Link Posted: 5/2/2021 5:25:20 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:

You’re talking about “coil pins,”
View Quote
 yes

I’ve had a little experience with coiled spring pins, and I wasn’t impressed.  Supposedly these let you install trigger guards without as much risk to the receiver’s ears.  They also don’t work as well with roll pin punches, and the one I’m thinking of wanted to expand out the end from the inside while I was installing it.  F-that.  I got the specified roll pin, used a nifty little screw clamp tool to install it, and that pin hasn’t moved a micron since.
View Quote


In 17yrs of building and shooting ARs I've found none of this to be true.  They work fine with roll pin punches and roll pin holders.  They do make trigger guard installation easier.

But thats not what this thread is about.
Link Posted: 5/2/2021 7:04:08 PM EDT
I was simply trying to clarify.  Then of course I added a bit more, based on a sample size of 1.  Sorry for the derail.

So far, the best non McMaster source I’ve found is Grainger, and they still sell in 100-quantities.  (McMaster’s prices for those quantities are MUCH better.)

Fastenal doesn’t stock coiled spring pins - they have pretty much all the slotted spring pins ever though.

Spirol invented the coiled spring pin.  They seem to have every size imaginable.  But they sell in lots of 1,000…
Link Posted: 5/3/2021 12:21:21 AM EDT
You could try Ace Hardware.  The fastener isle with all the trays has some odd and interesting hardware.
Link Posted: 5/3/2021 4:39:05 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:

You’re talking about “coil pins,” rather than “real roll pins”?
THIS: https://www.mcmaster.com/mvc/contents/gfx/imagecache/957/[email protected]_636961308946858127.png    NOT THIS: https://www.mcmaster.com/mvc/contents/gfx/imagecache/923/[email protected]_636961313429660031.png
Images from McMaster-Carr’s pages for these products.

McMaster-Carr makes it easy to differentiate the two types.  “Slotted spring pins” are what everybody thinks of as “roll pins,” and these are what the AR platform was designed to use.  These pins deform as you install them, then hold themselves firmly in place - which makes them a little harder to remove and replace.

The other type is called “Coiled spring pins.”  Their virtue is that they remain flexible once installed.  Which means, while they’re somewhat easier to install and remove, they don’t stay as firmly in place in AR applications.

I’ve had a little experience with coiled spring pins, and I wasn’t impressed.  Supposedly these let you install trigger guards without as much risk to the receiver’s ears.  They also don’t work as well with roll pin punches, and the one I’m thinking of wanted to expand out the end from the inside while I was installing it.  F-that.  I got the specified roll pin, used a nifty little screw clamp tool to install it, and that pin hasn’t moved a micron since.
View Quote

The slotted spring pins are generally stronger,too.
Link Posted: 5/3/2021 7:46:19 PM EDT
[Last Edit: 5/3/2021 7:47:37 PM EDT by Tigwelder1971]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By lysanderxiii:

The slotted spring pins are generally stronger,too.
View Quote

Everything that I've read has stated the opposite. (Granted, most information is from a structural / engineering POV and not directly related to AR applications).


Slotted pins have the sheet material coiled by less than one revolution, leaving a slot along the length into which the pin can compress. They are generally used for light-duty applications or where a slightly more accurate and rigid location is required.

•Coiled or spiral roll pins coil the sheet material by more than one complete revolution, typically about two full revolutions, so that the sheet coils toward the center. This enables them to be made from thinner, more flexible material while achieving a greater overall strength. This means that they are able to withstand a greater shear force than a slotted pin while also being more flexible. 

•Coiled Pins spread compressive stress over the entire pin and do not have stress point concentrations. Comparatively, Slotted Pins compress by closing the slot, and stress is concentrated 180 degrees opposite the slot


Link Posted: 5/3/2021 9:33:37 PM EDT
If you read the strength rating on them for the sizes used on AR's they are generally not as strong as a slotted pin. They make a heavy duty coil pin that is as or stronger than a slotted pin.
Link Posted: 5/3/2021 9:54:59 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By j3_:
If you read the strength rating on them for the sizes used on AR's they are generally not as strong as a slotted pin. They make a heavy duty coil pin that is as or stronger than a slotted pin.
View Quote

The heavy duty pins only get stronger above 1/8 inch diameter.
Link Posted: 5/3/2021 9:58:38 PM EDT
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Originally Posted By j3_:
If you read the strength rating on them for the sizes used on AR's they are generally not as strong as a slotted pin. They make a heavy duty coil pin that is as or stronger than a slotted pin.
View Quote

Good to know.

Most/if not all discussion regarding coil/split pins is geared toward mechanical fastening in higher stress areas than typical AR sizing. Personally, I can't see worrying too much regarding strength so long as the pins have the ability to retain position.

I do prefer coil pins if for nothing more than ease of installation.
Link Posted: 5/3/2021 9:59:15 PM EDT
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Originally Posted By lysanderxiii:

The heavy duty pins only get stronger above 1/8 inch diameter.
View Quote

Also good to know. Thanks.
Link Posted: 5/3/2021 10:09:30 PM EDT
[Last Edit: 5/3/2021 10:24:15 PM EDT by lysanderxiii]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Tigwelder1971:

Everything that I've read has stated the opposite. (Granted, most information is from a structural / engineering POV and not directly related to AR applications).


Slotted pins have the sheet material coiled by less than one revolution, leaving a slot along the length into which the pin can compress. They are generally used for light-duty applications or where a slightly more accurate and rigid location is required.

•Coiled or spiral roll pins coil the sheet material by more than one complete revolution, typically about two full revolutions, so that the sheet coils toward the center. This enables them to be made from thinner, more flexible material while achieving a greater overall strength. This means that they are able to withstand a greater shear force than a slotted pin while also being more flexible. 

•Coiled Pins spread compressive stress over the entire pin and do not have stress point concentrations. Comparatively, Slotted Pins compress by closing the slot, and stress is concentrated 180 degrees opposite the slot


View Quote

This would be true if they were made from the same material.  However, the slotted pins are made from stronger stuff.

There is also a little advertising hyperbole in the copy, the fact the the spiral pin spirals means that the contact area of the spiral pin looses contact over 1/4 of the pin (where the sheet starts to tuck under).  Because the slotted pin is a spring it will fill the entire hole, whether round or oval.

The real reason industry usually selects spiral pins over slotted pins is when the pins are installed in a automated process.  Slotted pins have a tendency to interlock in bulk storage bins.



Link Posted: 5/3/2021 10:22:25 PM EDT
So for the sake of getting back on topic, what is the size of the coil spring used for a gas block? I'll buy 100 from McMaster and mail a couple to OP
Link Posted: 5/3/2021 10:28:08 PM EDT
[Last Edit: 5/3/2021 10:36:59 PM EDT by lysanderxiii]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By doyouquaxu:
So for the sake of getting back on topic, what is the size of the coil spring used for a gas block? I'll buy 100 from McMaster and mail a couple to OP
View Quote

5/64 diameter by 5/16

98296A122 - 800 lbs double shear strength

OR

91598A632 - 550 lbs double shear strength
Link Posted: 5/3/2021 10:34:17 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By lysanderxiii:



There is also a little advertising hyperbole in the copy, the fact the the spiral pin spirals means that the contact area of the spiral pin looses contact over 1/4 of the pin (where the sheet starts to tuck under).  Because the slotted pin is a spring it will fill the entire hole, whether round or oval.

View Quote

Colt BCG.
Attachment Attached File

Link Posted: 5/3/2021 10:39:10 PM EDT
[Last Edit: 5/3/2021 10:44:45 PM EDT by lysanderxiii]
Discussion ForumsJump to Quoted PostQuote History

Yup.

And, you can see the little gap where the coil ends.

What is that holding it, an extra weight in the back of the carrier?

Link Posted: 5/3/2021 10:48:52 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By lysanderxiii:

This would be true if they were made from the same material.  However, the slotted pins are made from stronger stuff.

There is also a little advertising hyperbole in the copy, the fact the the spiral pin spirals means that the contact area of the spiral pin looses contact over 1/4 of the pin (where the sheet starts to tuck under).  Because the slotted pin is a spring it will fill the entire hole, whether round or oval.

The real reason industry usually selects spiral pins over slotted pins is when the pins are installed in a automated process.  Slotted pins have a tendency to interlock in bulk storage bins.

https://i.imgur.com/ucCJVzi.png

View Quote

Interesting. I hadn't noticed that before.

Link Posted: 5/3/2021 11:16:46 PM EDT
[Last Edit: 5/3/2021 11:18:11 PM EDT by j3_]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By lysanderxiii:

The heavy duty pins only get stronger above 1/8 inch diameter.
View Quote

That is incorrect according to two sites I checked. 1/16", 3/32", and 1/8" were listed higher with 5/64' being listed as equal.
Link Posted: 5/4/2021 9:21:06 AM EDT
Link Posted: 5/4/2021 9:27:28 AM EDT
[Last Edit: 5/4/2021 9:28:09 AM EDT by j3_]
Maybe the ejector retaining pin but the heavy duty coil pins are not really what I would call high strength. Example numbers off one site for a 1/16" pin only shows a small difference of 430 for a split type pin and 450 for a heavy duty coil type. The 5/64" are shown as equal between the two.
Link Posted: 5/4/2021 9:43:41 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By PursuitSS:
Can someone please enlighten me as to where a high strength pin is needed in an AR-15?
View Quote


It really is much ado about nothing.  I have zero issues installing split pins.
Link Posted: 5/4/2021 9:58:38 AM EDT
[Last Edit: 5/4/2021 10:00:31 AM EDT by hottnucks]
You should be able to order individual coiled pins from Rock River Arms and they have cheap USPS First Class shipping as well if I recall correctly.

ETA:

Lower Parts here: https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1349

Upper Parts here: https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1335
Link Posted: 5/4/2021 1:10:29 PM EDT
This is kind of on topic: is there an industry standard for the relationship between the actual hole size and the nominal pin size?  Like how much of an interference fit (after the pin deforms in installation) is the norm…

It seems to me that there might be different standards for slotted and coil pins because of how much each can compress.

I’ve always thought that where an AR part needed to be secured for heavy duty purposes, a solid pin, or even a taper pin was used.  Slotted roll pins, on the other hand, seem to be there for “holding something in place” like the gas tube, or “giving something an axle to move on without having to deal with threaded fasteners” like the trigger guard or bolt catch.

None of the places that have roll pins in an AR seem to have any strong forces applied to them.  Conversely, whatever type of pin is there, that pin’s job is to stay put.  I find it interesting that there are well developed commercial kits to replace the bolt catch pin with a threaded fastener, and all of them have to work at not coming loose because the catch pivots.

Notice how I’m not invoking Saint Stoner and how “in his wisdom” he did this or that…instead I’m thinking of the industrial design aspect, and how one roll pin replaces a screw, a nut, and some way to lock them together.
Link Posted: 5/5/2021 3:56:42 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By PursuitSS:
Can someone please enlighten me as to where a high strength pin is needed in an AR-15?
View Quote

FSB taper pins have to be of decent material to wedge the fsb down to the gas port.

Link Posted: 5/5/2021 4:49:18 PM EDT
Link Posted: 5/5/2021 7:41:58 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By GHPorter:
This is kind of on topic: is there an industry standard for the relationship between the actual hole size and the nominal pin size?  Like how much of an interference fit (after the pin deforms in installation) is the norm…

It seems to me that there might be different standards for slotted and coil pins because of how much each can compress.

I’ve always thought that where an AR part needed to be secured for heavy duty purposes, a solid pin, or even a taper pin was used.  Slotted roll pins, on the other hand, seem to be there for “holding something in place” like the gas tube, or “giving something an axle to move on without having to deal with threaded fasteners” like the trigger guard or bolt catch.

None of the places that have roll pins in an AR seem to have any strong forces applied to them.  Conversely, whatever type of pin is there, that pin’s job is to stay put.  I find it interesting that there are well developed commercial kits to replace the bolt catch pin with a threaded fastener, and all of them have to work at not coming loose because the catch pivots.

Notice how I’m not invoking Saint Stoner and how “in his wisdom” he did this or that…instead I’m thinking of the industrial design aspect, and how one roll pin replaces a screw, a nut, and some way to lock them together.
View Quote

Between the spiral and slotted pins, there is little difference, generally both require a 0.010" interference, with the hole at the nominal.

Seeing as Spirol, the guys that invented the spiral spring pin, make both spiral and slotted spring pins tells you there are applications where one is superior to the other.
Link Posted: 5/5/2021 10:02:54 PM EDT
[Last Edit: 5/5/2021 10:03:10 PM EDT by 11C1P]
Well, I'm sure if somebody came out with anti-walk roll pins they'd sell like hot cakes & you'd have people saying there were a MUST have on any AR you want to trust your life with.
Link Posted: 5/6/2021 8:45:15 PM EDT
BRD Engineering has 1/8 SS Roll pins in sets of 5 for $15.  To be used on gas blocks that they use for their gas block pinning jigs.

BRD Roll pins
Link Posted: 5/6/2021 9:11:22 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By 11C1P:
Well, I'm sure if somebody came out with anti-walk roll pins they'd sell like hot cakes & you'd have people saying there were a MUST have on any AR you want to trust your life with.
View Quote


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