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Chordate
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3D printing
This has been circulating social media sites for a bit, but I just stumbled on it and found it interesting.
Thingverse recently weighed in on the recent posting of a set of 3D printer designs for functional AR-15 lower receivers and magazines. Their verdict:
its a-ok. Magazines is somewhat interesting, but the lower receiver is presently the only part of the rifle which bears the serial number by which
firearms are tracked. All other parts can be purchased over the counter.
This is perhaps the first case I know of where the capabilities of easy at-home manufacturing are dramatically empowering (wrong word?) individuals to
break the law. One day we may see easy computer assisted manufacture of everything from designer clothes to designer drugs, but this to me looks like
the first stone.
What do you think, SM. Is this a dark day or a bright day? Is this a growing threat or a growing promise, and should this sort of thing be regulated
in a special way or should we rely on existing legal tools to prosecute counterfeiters of goods and creators of potentially dangerous tools?
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Endimion17
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Are you asking this question bearing United States in mind? Because if you do, you have to mention that. The situation in that country is already
severe because of the, by standards of the most countries, ridiculous, absurd and shocking law regarding firearms.
In most of the world, except USA, buying firearms requires a licence which is given after a citizen proves his/her sanity, etc. And if you have a
record of criminal behaviour, there's no way you'll ever be able to legally obtain any of it.
So I'd imagine that 3D printing would be a benign thing. You can't machine a safe, functioning rifle out of gypsum/polymer.
But in USA, where you can buy rifles and no one will bug you about it (and the government thinks of banning handheld lasers  ), one could very well be able to stock printed lower parts you're talking about. So
there's a difference. As usual, things that apply in USA do not apply elsewhere.
It's funny how a dysfunctional system once founded in pure and good concepts corrodes itself in a neverending feedback loop. Reminds me of communism
which rusted like an old drum left outside.
If you sense a hint of satisfaction in my post, don't take it too personally. I'm just commenting the pure irony, and by no means enjoy observing
anyone's misery.
[Edited on 25-9-2011 by Endimion17]
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Chordate
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In the U.S. any domestic violence problems (restraining orders, etc.), or any felony criminal behavior will prevent you from legally owning a firearm.
Purchasing a firearm from an authorized dealer requires an on the site FBI background check for this. Private sale is still an enormous loophole in
this, but this is bigger than that. With private sale there is still a traceable firearm and a history for the weapon that can be used to trace the
weapon.
I would say this is universally applicable. Almost every country tracks firearms by the receivers. As for the inability able to manufacture a safe,
functioning rifle out of polymer, this is moot. All other parts can be easily obtained almost anywhere, and several commercial arms, including AR
variants, are already made with polymer receivers. some 3d printers now have the ability to work with materials which are stronger than steel, and
last I checked no one is controlling the purchase of carbon composites.
This is something of a distraction though. What about home manufacturing capability in general? Long before we get to full blown atom by atom
construction it will be feasible to print very complex devices, from autonomous robots capable of performing industrial espionage to printed circuits
which intercept cell phone signals to large reaction vessels which might be used in drug or chemical weapons manufacture. Its a can of worms is what
it is.
How do we deal with it in a way that keeps it from nefarious uses while still preserving its utility for the innocent tinkerers and inventors?
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Endimion17
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I'm aware of the danger, but I think we're still very far from such scenarios. What you're describing is a crude replicator, like in Star Trek, but
without the bullshit part. In 50-75 years, likely. In the near future no. People will try, but rifle explosion chambers are a tough nut.
We're far from that, but nevertheless, I'm sure the "Big Brother's" strategies will evolve and try to control and follow most of the attempts you
imagine.
However, there's will always be a way to avoid them. Total control and absolute power is not possible, and thank god for that. (this
is a phrase, I'm not really considering supernatural concepts  )
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Polverone
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Here's another clever, criminal use for 3D printers.
I think that their benign creative uses far outweigh their potential for criminal use. I hope that their prices, capabilities, and market acceptance
continue to improve so that I can have one myself some day.
PGP Key and corresponding e-mail address
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gregxy
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All the 3D printers that I have seen can only make plastic parts which
would not work well for an AR-15 receiver.
Making guns in the USA is perfectly legal as long as it a type of gun that is
legal to own and you can legally own fire arms. No markings are required
as long as you don't sell the gun. Go to calguns.net to find out more.
Many companies sell "80%" receivers for the AR-15 AK-47 1911 and others. Most
of the work has been done for you but you typically need a fair amount of mechanical
skill and a few special tools (which are also sold) to finish the process. Black powder
guns are not even considered firearms by federal law and you just need to be 21 to
buy them.
The nanny state has banned most things that are dangerous but guns are protected
by the 2nd amendment so there are all kinds of strange laws.
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Chordate
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Quote: Originally posted by Endimion17  | | I'm aware of the danger, but I think we're still very far from such scenarios. What you're describing is a crude replicator, like in Star Trek, but
without the bullshit part. In 50-75 years, likely. In the near future no. People will try, but rifle explosion chambers are a tough nut.
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The lower receiver is not an explosion chamber. It servers to hold the magazine and trigger mechanism and guide the bullets into the path of the
bolt/chamber mechanism found on the upper. The recoil of the bullet is primarily absorbed by the bolt which is thrown against a spring mechanism in
the butt-stock to absorb the majority of the forces. The biggest challenge would not be the explosion, but rather selecting a composite which will not
deform excessively when in contact with a hot metal barrel. This is doable.
As for replicators, that level of fine control isn't needed for much of the things I am talking about. Colloidal graphite oxide when exposed to light
forms a thin conductive layer that has already been explored for printing circuits. This would also allow printing of antenna, while existing 3d
printing techniques would allow the printing of small mechanical parts. All that would be needed afterwards is purchase of the
microprocessor/controller parts that could be installed in the device as it was constructed by a careful hand or with machine aid. Software for such
devices is just as easily distributed electronically as the plans might be.
One can easily imagine designing small robots with mesh networking capability which could be attached to any exposed wire and feed parasitically off
the line's voltage which might autonomously distribute themselves through a building by maximizing distance from each other and then transmitting some
sort of useful information from the environment in a repeater fashion such that it could be picked up from outside a given building. This would be a
brilliant espionage tool
The only advances necessary would be a multipart 3D printing head with multiple tiny spinnerettes for different materials and higher printing
resolution for these heads. Not the sort of thing which would take 50 years to develop. More like 20 years. Consider that 75 years ago predates world
war 2. 40 years ago we went to the moon. I think 50-75 years is being generous, but who knows, maybe it's farther off than I think.
But again: Tip of the iceberg. As these devices become ubiquitous one could print everything from fake license plates to weapons parts to what have
you. These are ideas that are just emerging and the technology has only been narrowly available for a few short years. Imagine what the creepy folks
at megalomania might have done with it.
True replicators have even more potentially nefarious purposes. From crnano.org
| Quote: | | Molecular manufacturing raises the possibility of horrifically effective weapons. As an example, the smallest insect is about 200 microns; this
creates a plausible size estimate for a nanotech-built antipersonnel weapon capable of seeking and injecting toxin into unprotected humans. The human
lethal dose of botulism toxin is about 100 nanograms, or about 1/100 the volume of the weapon. As many as 50 billion toxin-carrying
devices—theoretically enough to kill every human on earth—could be packed into a single suitcase. |
So... Registry of some sort? Or just let the chips fall where they may?
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Endimion17
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Yeah, I know the lower receiver is not an explosion chamber. But in order to have a functioning rifle, you have to have both parts, so to say. Who
would profit from a manufacture of that? People who have access to the "upper part". You can't do anything without it. A functioning rifle is an
assembled rifle.
Almost everything I can think of can be made without 3D printers. The only "danger" lies in the fact that with them, illegal things became easier to
obtain.
But that's thinking in one dimension. Sort of like the ideas made by people back in 19th century.... or 1950s.
Predicting the future trends is an impossible task because society is not a linear system.
Here's a funny view on the subject.
http://www.terrycolon.com/2features/future.html
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bbartlog
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Firearms are crappy weapons in many ways, anyway. They do have great range (for a personal weapon) and immediate effect, but on the downside they
- are normally easy to detect (metal parts, relatively big)
- make a loud noise
- coat the user with nitrate residues
- aren't easily disposed of
Not exactly a superweapon. I think Chordate is on the right track: the problem is not going to be people who rehash existing tech on a 3D printer, but
people who actually make use of the new technology to implement previously unknown weapons of destruction.
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hinz
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And why not build a simplified AK47/Sten from scratch? The AR15/M16 is overengineered, there are so much more simple guns around which work better.
Given the fact, that the only parts of a gun which are not machinable without special equipment is the barrel rifling (except you have/build a barrel
rifling machine) and the cartridges.
The rest could be manufactured in a small workshop with a lathe, a forging oven and anvil, a mill and some files.
So if I would want to have a gun I would rather build a Sten like blowback gun instead of printing an AR15 receiver which probably blows up after a
few shots. Probably is easier to design and build something like a roller locked gun (easier since there are no asymmetric parts) from an existing
AR15 barrel than getting the 3d printed lower receiver rigid and heat resistant enough, so that the AR15 won't blow up.
OK, maybe I was a bit quick with my judgement, these pics look quite promising, better than most parts I've seen from 3d printers:
http://www.powerstrokenation.com/photopost/data/721/medium/3...
http://www.powerstrokenation.com/photopost/data/721/medium/t...
[Edited on 29-9-2011 by hinz]
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peach
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| Quote: | | Firearms are crappy weapons in many ways, anyway. |
They are excellent weapons. There is nothing so simple and yet so powerful as a bit of explosive with something wedged in the way. Which is why they
have been in used for centuries and we still have no space aged laser pistols despite having had relativity for a century.
The energy density of a battery or capacitor is never going to match that of an explosive. So, unless we come up with tiny nuclear power plants and
antimatter energy storage cells that are as reliable and cheap as explosives, there's no way to juice up that horribly inefficient laser pistol, rail
gun or particle cannon to begin with. And to do what? Burn a dot on someone.
Like the electric cables hanging from transmission lines, bullets have been and will be around for a long, long time.
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bbartlog
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Those your CNC lathe and milling machine? Now I'm jealous :-). Reminds me of the days when I worked in my dad's machine shop, years ago (1992-1994,
roughly). Wish I still had such equipment, though as a practical matter it just encourages further expenditure on metal stock, jigs and fixtures, and
tungsten carbide tooling.
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watson.fawkes
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That's a problem?
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franklyn
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3 D printing is way cool , it will change evrything we now know about
manufacturing when you can just have an appliance at home that can
replicate whatever you please just by downloading the design online.
Not there yet but many parties are working toward that.
http://www.cnbc.com/id/49329268
http://news.yahoo.com/cardboard-bicycle-change-world-says-is...
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497
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Nearly every technology can and will be used for both "good and evil" but as the technological "human power multiplier" increases exponentially (like
the last few decades) a few people abusing it have gained exponentially more control. So now what?
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ElectroWin
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This is a political hot-potato.
A machinist tells me that the creators of the above specifications had a rental contract with a CNC machine provider that was cancelled by the
provider, and the machine recalled, so that the provider would not be blamed.
You probably need a valid weapons manufacturer's license if you want to actually make a firearm. if people work to circumvent the rules, then
governments will extend the rules. this could be anything from making it illegal to 3D-print the receiver, all the way up to the horrible consequence
of criminalizing 3D-printers themselves.
in my opinion, the parts that should have serial numbers and be controlled, are the parts that match forensic capabilities of law enforcement and make
the weapon work. that would be, the barrel and the part of the assembly that guides the firing pin, since fired bullets and spent shell casings are
compared forensically, in investigations. is that practical?
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Swede
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As mentioned, USA laws are very different, and you can legally make any firearm you could otherwise legally buy.
The 3D printed AR lower is a fact, and it apparently works.
I've got a nice little machine shop and some modest skills. If some genie made every firearm in the world vanish instantly, I could probably crank
out a STEN or some other tube gun in a day or two. They are not difficult.
Interestingly, the EASIEST firearm to build would be a machine gun, not a semi-automatic weapon. The STEN is a perfect example. It has no firing
pin. The bolt simply reciprocates back and forth, and is held back by the trigger, so the moving parts would consist of a bolt, a spring, a trigger,
and maybe an extractor.
The machine shop comes in very handy turning plastic components like PTFE, PET, Acetal, and others, for some custom chemistry setups, especially
dealing with electrochemistry.
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gregxy
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You may be able to print the lower receiver but good luck
with the barrel and chamber. Guns operate at 20,000 to 60,000 psi. The barrel and chamber are normally made from hardened alloy steel with tolerances
of 0.0001 inch.
Of course you can just buy the barrels because it is legal to make guns for your own use in the USA. (As long as you can legally own a gun and the
gun is of a type that you can legally buy).
Printing guns is an interesting fabrication experiment but
has no significance to crime.
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franklyn
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@ gregxy
* Note that blowguns are made of two sections in which a groove is scored.
The two halves are then glued and bound together and the bore polished by
running a wad on a cord through it. Two halves of metal can be welded in a
similar manner and if it is thick walled rupture will not be a problem.
You seem to imply that a laminated barrel will fail due to the strain.
Not if it is axially laminated ( segments perpendicular to the bore )
This is the way the casing for hydrogen bombs is constructed so
that the detonation of the contained high explosives will not break it
before the resulting fission can be coupled to ignite the fusion fuel.
A cylinder constructed this way is enormously stronger than one the
same size made of solid metal. Punching out rings out of electroplated
machinist's shim stock , then assembling them over a removable core
so that they can be braised into a monolithic tube will serve the purpose
well. To protect it from bending and breakage it should be pressed
into a tube of steel.
Washers can also be friction welded together on a lathe or drill press.
Also termed spin welding or inertia welding.
http://www.youtube.com/watch?v=-aEuAK8bsQg
http://www.youtube.com/watch?v=5JbnDXw-0pM
http://www.youtube.com/watch?v=K36P3H8x4ew
Improvisation with a router to weld thermoplastic
http://www.youtube.com/watch?v=pp76lfbSOKI
All thats really needed is a contact weld as here
http://www.youtube.com/watch?v=3r36u7ZyitI
An important consideration is whether to have a rifled bore or a smoothbore ,
in the latter case common pipe would do as well as anything for a shotgun.
A barrel will need to be rifle drilled or at least reamed and then rifling grooves
cut within. This requires specialized tooling which is far more expensive than
the much simpler expedient as gregxy points out , to buy a barrel.
You also need to know how to do this as it is a trade of a skilled gunsmith.
I recall a documentary on the craft manufacture of small arms in Afghanistan
bordering Pakistan. Barrels are made of cement reinforcing bars , the trick is
in having the skill to heat treat the steel to the desired properties.
Case hardening is a way of mimicking the proper gun quality alloys.
http://www.irinnews.org/InDepthMain.aspx?InDepthId=8&Rep...
http://news.bbc.co.uk/2/hi/south_asia/5066860.stm
Increasing Small Arms Lethality
http://www.dtic.mil/dtic/tr/fulltext/u2/a512331.pdf
http://www.sciencemadness.org/talk/viewthread.php?tid=5897#p...
[Edited on 30-11-2012 by franklyn]
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ScienceSquirrel
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I suspect that the hardest part of improvised weapons manufacture is making cartridges.
The UK and Germany made guns in the hardest parts of trhe war but ammunition was in short supply.
The French maquis, Polish resistance,etc fabricated firearms including Sten type sub machine guns but I do not think they made their own ammunition.
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Swede
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If we are talking apocalyptic scenarios, the most effective and easiest expedient firearm will be the flintlock. All you need is a projectile, and
black powder, plus a nice flint.
But if the scenario is guerilla warfare with an oppressive regime or force, I agree ammo would be difficult. The obvious way to get it is to capture
it.
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franklyn
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Pakistan's home cottage industry at it's finest
http://www.youtube.com/watch?v=FinRqCocwGE
<iframe sandbox width="560" height="315" src="http://www.youtube.com/embed/FinRqCocwGE" frameborder="0" allowfullscreen></iframe>
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MagicJigPipe
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| Quote: | | Of course you can just buy the barrels because it is legal to make guns for your own use in the USA. |
It's a bit more complicated than that. There are rules you must follow and a bunch of forms you must fill out. And in some states it's not legal at
all, I think.
But, in general, that's the way it works and the way it SHOULD work. Forms shouldn't even need to be filled out. Anyone who thinks differently--I
wonder how the cognitive dissonance of wanting access to hazardous chemicals yet wanting strict gun laws makes their brain feel.
I thought we couldn't talk about gun laws on this forum?!? I got my shit deleted for just posting information one time without giving a single
opinion...
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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Swede
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MJP, I don't know where you live, but the overwhelming majority of the U.S. States allow hobbyists to make any firearm they could legally buy OTC.
That means semi-automatic is OK, everything except machine guns, silencers, and DD, destructive devices. There are no forms to fill out.
They recommend you put a serial number on it, and a maker's mark, but even that is not required.
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gregxy
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Swede is correct. I researched it thoroughly then made my own AK-47 rifle (in California, which has more restrictive laws than most states). I have
fired the rifle at the local range in the presence of law enforcement personnel, they did not have any problems with it.
After reading up on 3d printers some of the industrial ones,
that do laser sintering are supposed to be able to use any alloy and have tolerances
on the order of 10um. These could make most of the parts that are used in guns,
but I still think the barrels would need follow up work with difficult to obtain tools.
However these type of machines are not what is available to hobbyists.
A similar topic is gene sequencing, these days you can send your sequence
to a company which will send back the finished protein. However it looks like
the lengths they will create are much too short to create something like a working virus.
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