Sciencemadness Discussion Board - 3D printing

3D printing

Chordate - 25-9-2011 at 04:04

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?

Endimion17 - 25-9-2011 at 05:19

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]

Chordate - 25-9-2011 at 07:49

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?

Endimion17 - 25-9-2011 at 08:49

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

)

Polverone - 25-9-2011 at 10:25

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.

gregxy - 25-9-2011 at 10:54

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.

Chordate - 25-9-2011 at 14:03

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.

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?

Endimion17 - 25-9-2011 at 14:39

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

bbartlog - 26-9-2011 at 14:50

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.

hinz - 29-9-2011 at 09:54

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]

peach - 29-9-2011 at 11:47

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.

bbartlog - 29-9-2011 at 13:32

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.

watson.fawkes - 29-9-2011 at 17:07

Quote: Originally posted by bbartlog

it just encourages further expenditure on metal stock, jigs and fixtures, and tungsten carbide tooling.

That's a problem?

franklyn - 15-10-2012 at 16:46

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...

.

497 - 16-10-2012 at 01:09

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?

ElectroWin - 16-10-2012 at 08:41

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?

Swede - 28-11-2012 at 06:36

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.

gregxy - 29-11-2012 at 11:32

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.

franklyn - 29-11-2012 at 15:50

@ 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]

ScienceSquirrel - 29-11-2012 at 18:35

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.

Swede - 7-12-2012 at 07:35

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.

franklyn - 21-12-2012 at 00:04

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>

MagicJigPipe - 22-12-2012 at 19:44

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...

Swede - 24-12-2012 at 07:27

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.

gregxy - 24-12-2012 at 11:50

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.

franklyn - 25-12-2012 at 21:34

Amazing resolution of detail
http://www.tgdaily.com/games-and-entertainment-brief/68252-t...

.

franklyn - 11-1-2013 at 23:19

People who rush out to purchase firearms in anticipation of gun control
measures are not part of the " gun culture." The " gun culture " already
has its arsenal stocked up. The " last minute shoppers " are people who
believe one day they may need a gun and may not be able to buy one.
These are the same people who clean out the hardware store before a
severe weather storm hits. http://www.cnbc.com/id/100374251

Banning the future
www.3dprinter.net/3d-printers-obsolete-firearm-controls-and-...

www.3dprinter.net ,

is a very good site dedicated to this emerging technology

.

[Edited on 13-1-2013 by franklyn]

franklyn - 13-1-2013 at 20:25

Lost wax casting is a means by which highly detailed objects can be cast in metal.
The wax object is covered in a ceramic which forms the mold. Upon heating the
wax is volatilized leaving the hollow form which is then filled with molten metal.

3D Printing can produce onto a stiff rod a plastic core representing the rifled bore
for a barrel on which ceramic powder is then bonded the same as in the lost wax
casting process. The item is then fired as are clay pots in a kiln leaving just the
hardened hollow ceramic barrel. This can be inserted into a heated metal pipe
which when it cools shrinks tightly to provide necessary radial strength. No metal
casting is required and the kiln is easily improvised with natural gas or charcoal
and a hairdryer for a blower.

View in particular the video cited here _
http://www.popsci.com/technology/article/2012-08/wiki-bluepr...

.

Swede - 14-1-2013 at 09:36

Using a 3D printer to make a pattern for lost-wax casting would be superb, but the plastic material would need to be compatible with the process, i.e. melt easily, and leave no significant residue when the ceramic mold is fired.

franklyn - 15-1-2013 at 21:56

Lost Wax Investment Casting
www.youtube.com/watch?v=cptlGzWYFEk
Detailed description
www.youtube.com/watch?v=TEQxwq5pKrQ

If a metal gun barrel is desired , a thermite mix is ideal for pouring molten metal.
The problem is with precisely including the small amount of additional elements
for a suitable hard alloy of say 4150 steel or 440 stainless steel. Because of the
inherent variables in the result this approach has difficulties. There exists ready
made thermite used for welding train rails - www.thermitalloys.com/foundry.html
Despite limited use for expedient repairs , there has been little development.

The same technique can produce a superalloy with no iron such as MP35N
35% Cobalt , 35% Nickel , 20% Chromium , 10% Molybdenum. This will
tolerate small impurities inevitably present from crucible founding. This
Metallurgy has been investigated since between the first and second world
wars. Here is a reference from 60 years ago.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1993009...
www.smithsadvanced.com/downloads/MP35N_AMI.pdf
www.latrobesteel.com/assets/documents/datasheets/MP35N_summary.pdf
www.latrobesteel.com/assets/documents/datasheets/MP35N_extended.pdf

As seen in the following depictions one can in principle fire a mixture of the
metal oxides , I only found one paper about thermite produced superalloys
Thermite type combustion synthesis and direct casting of intermetallic compounds and super alloys
Yamada O.; Matsumoto H.
www.amazingrust.com/Experiments/how_to/Thermite.html
www.amazingrust.com/Experiments/how_to/Thermite_pics-videos....
Fe Ni Cr demos
http://www.youtube.com/watch?v=MfIHtxaY8Jw
Cobalt
http://www.flickr.com/photos/thorius/4799545504
A universe of Thermites are listed in the appendices
Survey of Combustible Metals , Thermites , & Intermetallics for Pyrotechnic Applications
www.dtic.mil/dtic/tr/fulltext/u2/a419762.pdf

Single crystal directionally cast superalloy such as made for turbine blades is
very difficult to execute successfully because it requires a very accurate gradient
of cooling applied to the part as it forms over a period of up to hours. The mold
is also maintained in a vacuum to prevent inclusion of air being solvated into the
molten metal which produces impurities that serve as nucleation points for
other crystal formation. Initially the metal poured into the mold fills a " pigtail "
corkscrew shaped extension at the bottom which by it's shape allows only a
single crystal lattice to form upward to fill the entire mold cavity.
http://images.machinedesign.com/images/archive/fea0200jpg_00...

Application of 3D mold rendering to investment single crystal casting. Here the
use of 3D printing methods replace the first step in the process of production -
the original patterns for the part to be made and it's production molds which
used to be tediously handcrafted by skilled machinists.
www.manufacturing.net/articles/2012/05/casting-process-could...

http://blog.makezine.com/2012/01/16/single-crystal-superallo...
www.msm.cam.ac.uk/phase-trans/2003/nickel.html

Casting Processes ( directional solidification on page 41 )
www-old.me.gatech.edu/jonathan.colton/me4210/casting.pdf

www.thefreelibrary.com/How+it's+done:+single+crystal+casting:+the+techniques+used+in+the...-a0265978583

_________________________________________________________

An alternative to traditional metal parts is the use of reinforced composite materials.
Usually this is taken to mean an organic resin glass fiber matrix. This is adequate
for many parts and is presently used in many commercially produced firearms. The
durability and stress resistance of the principle functioning parts as barrels require
much stronger hard material. The same exact technique can be used with ceramics.
http://en.wikipedia.org/wiki/Ceramic_matrix_composite
An equal mixture of finely powdered borosilicate Pyrex and minute asbestos " whiskers "
can be fired so that the glass melts at ~ 820 ºC , the asbestos fibers do not melt until
a much higher temperature depending on the particular mineral form - up to 1500 ºC.
http://ces.iisc.ernet.in/energy/HC270799/HDL/ENV/enven/vol31...
The fibers remain intact and encased by the solidified glass to form a tough durable
material. An equal mixture of quartz Vycor powder which melts at ~ 1650 ºC , and
Silicon Carbide whiskers which melt at ~ 2700 ºC , can be used also , producing a
superior ceramic. The higher temperature required would make it difficult to fire in an
improvised kiln. Also , ceramic particles small enough to be inhaled pose a hazard in
the initial compounding of the powdered material and it needs to be safely handled.
www.acm-usa.com/Pages/Materials/detail.aspx
www.acm-usa.com/Pages/Materials/detail.aspx?fsId=0
www.acm-usa.com/site/user/files/1/Product_Datasheet__SC_9M.pdf

Analytic Model Development for Ceramic Gun Tubes
www.dtic.mil/dtic/tr/fulltext/u2/a441236.pdf

Mechanical and Thermal Properties of Advanced Ceramics for Gun Barrel Applications
www.dtic.mil/dtic/tr/fulltext/u2/a430400.pdf

5.56mm Ceramic Gun Barrel Thermal Analyses with Cycled Ammunition copy upper and lower strings separately and paste them together in the address bar
www.ciar.org/ttk/mbt/papers/isb2007/paper.x.isb2007.IB06.5_point_56mm_ceramic_gun_barrel
_thermal_analyses_with_cycled_ammunition.huang_conroy_carter.2007.pdf

.

497 - 16-1-2013 at 00:02

Love the sounds of those ceramic composites!

Maybe all this innovation crap is just to too good to be true... http://www.manufacturing.net/blogs/2012/12/the-patent-office...

gregxy - 16-1-2013 at 15:24

Those articles on ceramics are interesting but not very
encouraging for firearms. The best yield strengths for the
ceramics quoted were around 300MPa. For alloy steel
hardened to RC 35, which is typical for guns, the yield
strength is 1100MPa more than 3X higher. The steel
however can stretch up to 15% before total failure, the
ceramic only 0.7%. While stretching the steel absorbs
a tremendous amount of energy and allows the gun
to fail gracefully with a bulged barrel instead of blowing to bits in your face. Failures of this type do happen due
to incorrectly loaded cartridges.

From looking on the web there have been some experiments
with ceramic lined barrels, but I did not see anything in
production.

There is a website for home gunsmiths (I think it is
homegunsmith .com or .org.) They make some really
cool guns, but most start out with a barrel from an
old gun due to the difficulty of creating the rifling.
However there was a guy that did his own rifling
using a twisted strip of steel.

Black powder guns can be made at home since the
internal pressures are much lower 10,000PSI vs 60,000
PSI for a high power modern weapon. Plus you can
make your own powder and the ATF does not consider
them as firearms.

The shot heard around world - first 3D-printed gun fired

franklyn - 27-5-2013 at 18:16

Hurrah for chaos and anarchy !

www.cbsnews.com/8301-205_162-57583010/liberator-gun-made-wit...

Just to prove that you can't fix stupid :
New York Sen. Charles Schumer, called for a ban on printable weapons
" A terrorist, someone who's mentally ill, a spousal abuser, a felon can essentially open a gun factory in their garage, "

www.nypost.com/p/news/national/gun_is_lock_upload_mcSF4lQ6cp...
“ We’re facing a situation where anyone — a felon, a terrorist — can open a gun factory
in their garage and the weapons they make will be undetectable. It’s stomach-churning. ”

Duh , I'm with stupid

New York Congressman Steve Israel has called for national legislation to ban 3D-printed guns
" Now that this technology is proven, we need to act now to extend the ban on plastic firearms."

www.foxnews.com/tech/2013/05/06/shots-fired-from-world-first...

Our society would be better off if these persistent vegetative brain stems would ban themselves.
How can anyone for who getting a manicure , is the only first hand knowledge of manual labor ,
possibly be competent to govern manufacturing , are you starting to get the drift of why the U.S.
no longer makes anything. Everything they put their paws on is turned to shit.
In 1930 Detroit was the fastest growing city in the world. Today it is the fastest shrinking ,
with over 100,000 abandoned homes , it's going back to prairie.

www.atf.gov/firearms/faq/firearms-technology.html#commercial...
" per provisions of the Gun Control Act (GCA) of 1968, 18 U.S.C. Chapter 44, an unlicensed individual may make a firearm
as defined in the GCA for his own personal use, but not for sale or distribution."
" Individuals manufacturing sporting-type firearms for their own use need not hold Federal Firearms Licenses ( FFLs)."

www.foxnews.com/us/2013/05/23/govt-memo-warns-3d-printed-gun...
Homeland Security bulletin warns 3D-printed guns may be 'impossible' to stop
" Unqualified gun seekers may be able to acquire or manufacture their own guns with no background checks. "

Yeah , so long as there are people unqualified to express their unwanted opinion , but do so anyway.

Not to be upstaged , the State Department takes action.
www.wired.co.uk/news/archive/2013-05/10/defcad-gun-design-ta...
These titans of industry havn't quite put 2 and 2 together yet either.
How low down the evolutionary trunk do you have to be to still have doubts.
No desk bound cretin can subvert a handy man.

www.pcmag.com/slideshow/story/309243/defcad-3d-printing-mean...

.

elementcollector1 - 27-5-2013 at 19:19

Why wasn't this a problem before? I know plastic can't be detected by normal methods, but anyone with a decent metalworking ability should be able to build a working flintlock if they really set their mind to it.
Oh, but now that futuristic technology's involved, it's a problem. Ban the 3-D printers! Forestall the advance of scientific ingenuity! And especially don't trust anyone that has one already - they could be a terrorist and you don't. Even. Know it.

Zyklon-A - 29-1-2014 at 08:30

Here's what I think about this...

IrC - 31-1-2014 at 02:55

Quote: Originally posted by Zyklonb

Here's what I think about this...

Why are you hijacking the thread which is about making something high tech, by turning it into yet another left wing political bash fest by posting an anti gun video by a leftwing canadian whackjob. Franklin was not posting information about political viewpoints. All he was doing was posting details about the technology. The thread is about 3D printing. As an American know that I for one do not give a crap what the canadian in the video thinks about what goes on down here. None of his business. Nor do I think it is proper for you to post a video loaded with insults about people who believe in the Constitution, or owning firearms.

Watching the video:

At 2:00; "as usual, this is the part you ignore when you start leaving uninformed, poorly spelled comments about how much I hate guns (and therefore, America)"

At 2:42 tries to show a slanted statistic of guns used for self defense by omitting the five worst cities for examples, where FBI stats are far more accurate and show exactly the opposite conclusion. States in red an implied negative about Constitutional Conservatives "or at least that's what them commie liberals want you to believe so they can come take our guns". (Ironically by fixing the stats it is a self fulfilling prophecy on his part)

By 2:56 attacking and insulting the Bill of Rights, Founding Fathers, ignoring the true reason for the second Amendment by stating fallacies as a form of propaganda. Continues with repetition implied negatives about Constitutional Conservatives, including bringing in the 'tinfoil hat attack', singling out a tragic child involved gun accident and repeats it more than once as if it adds weight to his point of view. By implication these tragedies are out of control happening everywhere at astronomical levels, patently false. In general a nonstop 3D printing gun bashing typical left wing liberal attack upon gun ownership. Nothing but an anti gun political hit video which has no business being posted in this thread. Zyklonb by stating "Here's what I think about this..." is in effect also bringing this in as his view, off topic and improper in this thread. Ironic considering his name and the millions of murders of innocent people it represents. Even more ironic is those millions of murders could have been avoided had the victims not given up their guns when ordered by the government. Also ironic since the very reason for the Second Amendment in the first place (misrepresented in the hit video) is to protect from out of control murderous criminal government such as his namesake represents, not the hunting, sports, and home defense which is all the left ever considers.

Metacelsus - 31-1-2014 at 06:43

Quote: Originally posted by IrC

The thread is about 3D printing.

Agreed. There are plenty of other uses for 3D printing than guns. Please don't derail this thread into the morass of politics.

[closed]

bfesser - 31-1-2014 at 09:44

The OP was specifically targeted at the implications of 3D printing firearms. However, since this topic isn't about "regulatory and social issues <em>affecting scientific hobbyists</em>," it was on the verge of closure from the outset. The beginnings of a flamewar lead me to the decision to close this thread. If you want to continue discussing firearms and the legal/moral implications of their manufacture, there are surely websites dedicated to the topic. If anyone would like to discuss the use of 3D printers <em>for amateur science</em>, please feel free to open such a topic—I'm sure it would be welcomed by all.

<strong><a href="viewthread.php?tid=25805">Does your post belong in Legal and Societal Issues?</a></strong>

3D printing

The shot heard around world - first 3D-printed gun fired

The plastic ' zip ' gun

All metal

All carbon

[closed]