View Full Version : 3-D printing some anti-tilt mag followers
Serial_killer
02-11-13, 12:15
I have been wanting to update all my USGI mags, I have 18 total, 4 of which had magpul rebuild kits with the new style anti-tilt followers. One mag is not working at all and has to have a new follower to be fixed. Not being able to find more anywhere I've been thinking about modeling off one I already have and 3D printing some more.
The 3D printer I have access to (tho I'm pretty sure they're all the same in the medie aspect) uses a type of ABS plastic, I'm not sure the exact composition but the cartridge says "ABS, P400, for dimensional printing". Would this ABS plastic hold up and be suitable followers?
Of course the mags work as-is with the green followers, I just thought this might be a cool project. I'm just trying to gauge if its even worth it or if the followers are just goin to break apart upon first use.
I know some people have printed lower receivers, I also watched a show on NatGeo there they printed a big adjustable wrench and actually used it to tighten/loosen a metal bolt. Personally I've only seen the printer I have access to be used for modeling purposes but I'm sure it's all the same technology.
My other idea/option is to make some followers out of a block of HDPE on my mill, it sure would be easier to just make one CAD model and push print as many times as I need than to stand there and mill them out over and over, my mill is manual, not CNC, the 3D printer is of course fully automated, once I model the follower in the CAD program I can repeatedly print more with minimal work.
Mods- this seems like an advanced technical AR topic to me but if I've posted it in the wrong forum, or if it would be better somewhere else then I'm sorry
Magic_Salad0892
02-11-13, 12:45
There was an article not long ago on 3-D printable magazines, the followers themselves were printed too. The only thing that wasn't was the spring. And the dude who did it said that his mags were working.
I'd think that the follower itself would be okay to print.
If you're planning on modeling one of the Magpul followers, you might consider retaining the services of an attorney to help defend you from a Magpul lawsuit on patent infringement. Just something to consider when carried away in all of the excitement. :D
One mag is not working at all and has to have a new follower to be fixed.
Two questions:
What malfunction is that particular magazine inducing?
How is a follower change going to correct it?
Serial_killer
02-11-13, 13:15
Two questions:
What malfunction is that particular magazine inducing?
How is a follower change going to correct it?
The follower is broke, it is going to correct the problem via the old follower is in pieces and whatever new one I make won't be.
As for the other comment about the lawsuits, I wont copy a magpul follower, I'll copy a c-products one, they won't be going after anyone (not to mention magpul never went after c-products and they did do it commercially). But really tho they won't care, I'm not making them to sell, I'm not using the same materials, I'm doing it ONLY for personal use and on top of all that I really doubt they're going to be EXACT replicas, it's not like its a 3-d copy I just put the old one in and a new one comes out, I have to measure and design/model it myself, I'm sure there will be minor differences.
For the 2 guys who actually contributed thank you.
If you're planning on modeling one of the Magpul followers, you might consider retaining the services of an attorney to help defend you from a Magpul lawsuit on patent infringement. Just something to consider when carried away in all of the excitement. :D
There's a research exemption in patent law that would likely let him get away with it as long as he's not doing it with the intent to sell commercially or as part of a business.
An individual just playing around with a 3D printer to see if it could be done seems to satisfy the criteria for the exemption...
There's a research exemption in patent law that would likely let him get away with it as long as he's not doing it with the intent to sell commercially or as part of a business.
An individual just playing around with a 3D printer to see if it could be done seems to satisfy the criteria for the exemption...
I see your point and the OP's. Just wondering in the future when 3-D copying will be more precise and the correct material will be used. Picture someone having that capability making dozens for their own personal use and then letting friends do the same. No money changes hands, nothing was sold but someone is losing business. Yep newer technology brings along their own set of issues. Just look at all the counterfeits that are flooding the market that the original manufacturers have to deal with. Now compound that with what the general public can or will be able to replicate in the very near future.
TheAxeShooter
02-11-13, 14:01
I know a guy made some printed magazines, followers, and lowers a while ago. He uploaded all the blueprints online. I'm sure you can Google them. And as long as you don't sell them you're good. Print a few and see how they work.
I see your point and the OP's. Just wondering in the future when 3-D copying will be more precise and the correct material will be used. Picture someone having that capability making dozens for their own personal use and then letting friends do the same. No money changes hands, nothing was sold but someone is losing business. Yep newer technology brings along their own set of issues. Just look at all the counterfeits that are flooding the market that the original manufacturers have to deal with. Now compound that with what the general public can or will be able to replicate in the very near future.
If I knew where the tech and IP legal environment were going with respect to rapid prototype/rapid manufacturing, lets just say I wouldn't be going to my day job lol :D
http://defcad.org/ar-15-magazine/
Don't know it's anti-tilt or not, but that place should lead you to something.
There's a research exemption in patent law that would likely let him get away with it as long as he's not doing it with the intent to sell commercially or as part of a business.
Not as far as I know - no exceptions.
TheAxeShooter
02-11-13, 18:32
http://defcad.org/ar-15-magazine/
Don't know it's anti-tilt or not, but that place should lead you to something.
That's what I was talking about in my post. I just didn't feel like googling ha.
Not as far as I know - no exceptions.
http://scholar.google.com/scholar_case?case=13577625967649928741&hl=en&as_sdt=2&as_vis=1&oi=scholarr
In short, regardless of whether a particular institution or entity is engaged in an endeavor for commercial gain, so long as the act is in furtherance of the alleged infringer's legitimate business and is not solely for amusement, to satisfy idle curiosity, or for strictly philosophical inquiry, the act does not qualify for the very narrow and strictly limited experimental use defense. Moreover, the profit or non-profit status of the user is not determinative.
Now I'm no lawyer but I did stay at a Holiday Inn Express once and it seems to me that fiddling with a 3D printer to see if you can make something fits the idle curiosity criteria as long as he's not in the firearms business. As I read it, Duke lost the case because using the patents furthered their business of research and education.
He does not want it to experiment. He wants it to use instead of buying one.
BTW - obviously no one is going to go after you for making a follower. If they did, and it would be ridiculous to do so, but if they did, you would be out a lot of money before the case was dismissed. But that would never happen.
He does not want it to experiment. He wants it to use instead of buying one.
BTW - obviously no one is going to go after you for making a follower. If they did, and it would be ridiculous to do so, but if they did, you would be out a lot of money before the case was dismissed. But that would never happen.
This will be my last word because its pointless to argue such an inane legal matter without being a judge or lawyer, but to me, him wondering how to do it along with questioning the durability makes the experimentation case. Reading the case decision i linked in its entirety it seems like the entire intent of the exception is specifically to keep patent holders from coming after people playing around in their garage with no business or commercial intent.
Essentially its a legal construct in case the common sense in the second part of your post is absent. And i agree not even a patent troll is coming after an individual.
He is wondering about the strength and that is why he is making it? No. He stated he is making it because he is not able to find more for sale.
In any case, no one will mind a guy making one.
Just a little info on the defcad follower. The design will use about $3.60 in ABS plus material printing at .007 z slice and a .012 path width. Note, you need to remember that the layers are fused together which reduces the strength. Almost like grain in a piece of wood. Build orientation is very important to achieve the testing results you're looking for.
http://powerstrokearmy.com/photopost/data/542/follower.jpg
Spec's on the material:
Tensile Strength (Type 1, 0.125”, 0.2”/min) ASTM D638 5,300 psi
Tensile Modulus (Type 1, 0.125”, 0.2”/min) ASTM D638 330,000 psi
Tensile Elongation (Type 1, 0.125”, 0.2”/min) ASTM D638 3% 3%
Flexural Strength (Method 1, 0.05”/min) ASTM D790 7,600 psi
Flexural Modulus (Method 1, 0.05”/min) ASTM D790 320,000 psi
IZOD Impact, notched (Method A, 23°C) ASTM D256 2.0 ft-lb/in
GUNSLINGER733
02-11-13, 20:05
I'd make some. If you're not selling or making a 1009374748393ion who cares.
He is wondering about the strength and that is why he is making it?
No.
He stated he is making it because he is not able to find more for sale.
It would cost $30,000 - $600,000 to win a legal case, which is exactly the reason why no one would ever go after him either (besides not even caring that he did it).
Well i lied because im bored and the more i think about it the more interesting i think the question is.
The exception exists via the court decision i posted. Scotus declined to hear the case so it is the law of the land. IMO its a simple question that must be answered to determine if it fits namely "is it a private individual who is seeking to learn something?" if the answer is yes then the exception fits. I dont think the original rationale for attempting it as a private individual has any bearing.
That opinion and a smooth buck will buy you a hamburger at micky ds so take it for what its worth although this law review article seems to be saying the same...
http://www.finnegan.com/resources/articles/articlesdetail.aspx?news=a92ba957-47b0-4b97-9c78-1a4130257a92
Just a little info on the defcad follower. The design will use about $3.60 in ABS plus material printing at .007 z slice and a .012 path width. Note, you need to remember that the layers are fused together which reduces the strength. Almost like grain in a piece of wood. Build orientation is very important to achieve the testing results you're looking for.
http://powerstrokearmy.com/photopost/data/542/follower.jpg
Spec's on the material:
Tensile Strength (Type 1, 0.125”, 0.2”/min) ASTM D638 5,300 psi
Tensile Modulus (Type 1, 0.125”, 0.2”/min) ASTM D638 330,000 psi
Tensile Elongation (Type 1, 0.125”, 0.2”/min) ASTM D638 3% 3%
Flexural Strength (Method 1, 0.05”/min) ASTM D790 7,600 psi
Flexural Modulus (Method 1, 0.05”/min) ASTM D790 320,000 psi
IZOD Impact, notched (Method A, 23°C) ASTM D256 2.0 ft-lb/in
Ive never looked into it before, what kind of shear strength do the bonds between layers have? Seems like that would be a primary concern given the type of forces a follower sees in the anti tilt function
The shear strength between layers will be the weakest or failure point. If I lay the part down I would get the best usability based on strength but the dimensional accuracy will drop in the outer surface area that slides into the mag. Sanding or minor scaling of the model might be needed based on the clearance the designer incorporated in the part. You will also use more support material so overall part cost will increase by $0.59.
http://powerstrokearmy.com/photopost/data/542/follower-2.jpg
The follower is broke, it is going to correct the problem via the old follower is in pieces and whatever new one I make won't be.
Wait--how in the nine hell's did your mag follower break into pieces and yet the mag body is okay?
The shear strength between layers will be the weakest or failure point. If I lay the part down I would get the best usability based on strength but the dimensional accuracy will drop in the outer surface area that slides into the mag. Sanding or minor scaling of the model might be needed based on the clearance the designer incorporated in the part. You will also use more support material so overall part cost will increase by $0.59.
http://powerstrokearmy.com/photopost/data/542/follower-2.jpg
Got interested and dove down the rabbit hole last night. I wonder if it might be worthwhile to switch to a different material than ABS. These guys have a printable nylon that's supposed to have better layer to layer adhesion than ABS.
http://www.taulman3d.com/index.html
I've really got to get my shop set up so that I can get a 3D printer going.... :moil:
The follower is broke, it is going to correct the problem via the old follower is in pieces and whatever new one I make won't be.
As for the other comment about the lawsuits, I wont copy a magpul follower, I'll copy a c-products one, they won't be going after anyone (not to mention magpul never went after c-products and they did do it commercially). But really tho they won't care, I'm not making them to sell, I'm not using the same materials, I'm doing it ONLY for personal use and on top of all that I really doubt they're going to be EXACT replicas, it's not like its a 3-d copy I just put the old one in and a new one comes out, I have to measure and design/model it myself, I'm sure there will be minor differences.
For the 2 guys who actually contributed thank you.
Anywho, not commenting after the hockey game this time... PM me your address and I'll drop several green USGI's in the mail free of charge. That'll solve your immediate problem of a broken follower and you can experiment (while having a functional magazine) at will.
Jack Spectre
02-18-13, 13:22
The shear strength between layers will be the weakest or failure point. If I lay the part down I would get the best usability based on strength but the dimensional accuracy will drop in the outer surface area that slides into the mag. Sanding or minor scaling of the model might be needed based on the clearance the designer incorporated in the part. You will also use more support material so overall part cost will increase by $0.59.
http://powerstrokearmy.com/photopost/data/542/follower-2.jpg
The layer to layer strength, or "Z strength" is about 70% as strong as an injected molded part in ABS. There is no real shear force on the follower while it's inserted into the rifle. It's being compressed between the spring and the ammunition, but there's just not enough force to separate the layers.
I've built a full mag with a follower using a Stratasys machine. The follower is a pretty chunky block of plastic.
There is no real shear force on the follower while it's inserted into the rifle. It's being compressed between the spring and the ammunition, but there's just not enough force to separate the layers.
You'll see shear forces in the follower "legs" as they contact the sides and perform the anti-tilt function. That should also create a tensile load that will work to further stress the joint.
I need to scrounge some strain guages and instrument one of my old junk magazines to see just what magnitude of loads the follower sees....
Jack Spectre
02-19-13, 13:47
You'll see shear forces in the follower "legs" as they contact the sides and perform the anti-tilt function. That should also create a tensile load that will work to further stress the joint.
I need to scrounge some strain guages and instrument one of my old junk magazines to see just what magnitude of loads the follower sees....
That would be interesting data, to be sure. I think if you built the follow horizontally (your second configuration), you wouldn't be putting the stress on the layer interfaces.
Are you looking to have Redeye build the part?
That would be interesting data, to be sure. I think if you built the follow horizontally (your second configuration), you wouldn't be putting the stress on the layer interfaces.
Are you looking to have Redeye build the part?
I'm not the one planning on building it, at least not right now. I'm just trying to provide a little useful info in the one area I can be considered reasonably knowledgeable, namely engineering.
When I finally get around to building my shop, I do plan on having some CNC and 3D printing equipment in it for these sorts of interesting projects though.
And yeah, my back of the envelope stress assessment was based on a top to bottom buildup. If you can do either a front to back or side to side build up, I think you would mitigate the issue with layer bonding. I haven't looked at it closely enough to know whether either of those is possible or not...
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