Posted on 12/25/2012 7:07:57 PM PST by grundle
Demands for stricter restrictions on gun sales are all the rage right now in light of the Connecticut elementary school massacre. However, a law student at the University of Texas says new technology will soon change the regulatory landscape dramatically, and possibly make such regulation futile.
The student, Cody Wilson, is among the leaders of Defense Distributed, home of the wiki weapon project. The goal of the collaborative, nonprofit project is simple: to create freely available plans that you can download from the Internet and produce a gun using a 3-D printer.
YouTube video at printablegun.com shows Wilson’s group test firing a semiautomatic AR-15 rifle, reports KVUE, Austin’s ABC affiliate. An AR-15 was among the weapons Adam Lanza used in the Sandy Hook shooting.
According to Wilson, 24, the group used a 3-D printer to print a plastic lower receiver. The piece was then attached to the rest of a real gun. In a test that was unverified by any independent observers, the plastic piece broke, but not before the gun fired six live rounds.
“What I’m doing is showing people, okay, this is something that can be done right now with this technology, and we’re changing this in the software, and we’re making modifications and customizations and testing with different rounds and different guns, but what we make won’t look like a plastic AR-15,” Wilson told WVUE. “What we make will just be the gun at its most essential, something that just is a firearm practically speaking.”
The legality of printable 3-D guns is not clear. (RELATED: Democratic congressman urges renewal of plastic gun ban)
Democratic New York Rep. Steve Israel doesn’t want to take any chances, though, according to WVUE. Israel has called for the renewal of the Undetectable Firearms Act of 1988, which is set to expire in December 2013.
As Slate notes, the Act makes it illegal to “manufacture, sell, ship, deliver” or “possess” firearms that garden-variety metal detectors or x-ray machines can’t detect. A renewed act would presumably cover guns manufactured with 3-D printed gun parts, which are plastic.
OK, but just this once...
Wax specifically engineered for lost was casting is a standard 3-D printer material.
“Carbon fiber barrels are thin steel barrels wrapped with carbon fiber. You will never be able to print them.”
What of a ceramic bore?
Betcha that could stand more throat erosion than a chromed steel barrel.
Why go to brass?
AR receivers (uppers and lowers) are typically made of 7075 aluminum. You could make them out of just about any aluminum and they’d work. The 7075 alloy is just stronger than other aluminum alloys.
The melting point of aluminum alloys that would be useful here (6061 or 7075) are in the range of 900 to 1100+ degrees F. Brass alloys melt up in the high 1600’s to low 1800’s.
What many AR fanboys don’t realize is that, to those of us who work on old-fashioned guns made of steel and wood, AR’s are already effectively made from pot metal and plastic.
AR
The important parts are made of steel.
May all of our enemies be as stupid as this fool.
Yes, it could, but why bother? Ceramics are brittle. The first time you dropped a ceramic barrel, it would probably shatter or break.
There are already 3D printers that are making complex shapes from for-real alloy steel and stainless steel. The process is called “direct metal laser sintering,” and the Germans are in the lead on the technology (and the machines). Right now, the machines are ferociously expensive and they require a fair bit of power, but they make for-real metal parts that handle high temps to tight specs.
Once you have a chrome-moly alloy steel barrel, you just salt bath nitride it and it will have a case hardened layer that’s harder than the hinges of hell.
Yes, they are.
But they’re surrounded by pot metal and cheese-whiz.
Well I know nothing about guns or 3-D printers but I need to ask this.
On a recent CSI TV show, they figured out an assassin was using a gun made from a 3-D printer.
The scenario was that, yes it was destroyed by the single shot, but you also had a bullet with no lands and grooves.
If he needed to do another hit, he just printed another gun.
Is this possible or just TV hokum?
Yes and no. Like the original article, the screenplay is confusing 3D factors with things that are there for functional reasons. The rifling isn’t a side effect of the manufacturing process, the makers go to a lot of effort to put it there. So, yes you could make a smoothbore printed 3D, but so could you using old tech, and you could print a rifled barrel (given a satisfactory printer/feedstock) just as with conventional tech. IOW, a smoorebore/zipgun made with old tech would have the same advantages and disadvantages vs a rifled design as a 3D printed smoothbore would vs a printed rifled design. In fact, you could even argue that as much of a pain as rifling is, it might even be EASIER to print it, so there would be LESS incentive to print a smoothbore.
“Once you have a chrome-moly alloy steel barrel, you just salt bath nitride it and it will have a case hardened layer that’s harder than the hinges of hell.”
What is the corrosion resistance of nitrided chrome-moly v. stainless steel or c ceramic barrel?
It would not take much in the way of engineering know-how to fabricate a barrel out of steel bar-stock available at any machine ship.
A metal lathe, a drill press, a clamp and a micrometer are all easy to operate.
Being able to use a 3D printer to get the more involved bits would save some time.
The real issue as I see it is propellant. Making smokeless powder might be harder than making the weapon
Exactly.
People don’t seem to realize that guns are EASY TO MAKE. Really. They are.
The reason why so many people don’t realize this is that we’ve extirpated machine shop and practical mechanical classes from high schools so that we could make room for all manner of useless gibberish for the college-bound nitwits who don’t (and won’t ever) know their asses from a warm rock.
The only part on a gun that I can’t make and couldn’t teach you how to make easily in your own garage is the barrel. I take that back: I could teach you how to make a barrel, but it wouldn’t be an accurate barrel. And it would be much easier to teach people how to make pistol barrels in larger calibers, like a barrel for a .45, for example. Making small broaches and rifling buttons is harder than making big ones.
The rest of a serviceable firearm (especially a semi-auto pistol using a blowback design) I could teach anyone but the most inept tool-killing klutzes how to make in their garage.
Now, everyone has a major jones for AR’s just now. AR’s have a couple of interesting details that make them difficult (for the uninitiated) in how to deal with the inside voids like the magazine well.
Well, that’s no big deal. All you need to do is section an AR lower receiver lengthwise down the middle and cast the receiver in two halves - but leave on some bosses and alignment pins/holes to help you get the two halves together. Now you have a very simple issue to cast or make from aluminum bar stock on a mini-mill that could could buy at Horror Freights for under $1K. Add in another $500 in tooling and you’re in the business of making serviceable AR receivers.
Working in aluminum is PUD easy. Easy, easy, easy. It’s soft, it’s ductile, the most popular alloys (6061 and so on) are easily welded with oxy-acetylene or TIG (or even MIG) rigs, there are plenty of modern glues you can use to make snug-fit parts permanent joins, etc.
The roll pins for an AR can be had by the truckload from outfits like Fastenal.
The holes for the .154 pins are drilled undersized and reamed (with a straight chucking reamer) to size. The rear buffer tube mounting point is easily done if you align it in the mill vise and use a tap (which you can also buy from Fastenal as well as a dozen other tool companies) to cut those threads. Want to make a buffer tube? Another piece of aluminum and a die for threads. Oh, and you’ll need to fill the far end of the tube with a disc. More threading - just use green Loctite to glue the plug in the tube.
Springs? Easy. Wind piano wire around a form.
See where I’m going with this? THIS STUFF IS NOT ROCKET SCIENCE. I should know. I was force-fed orbital mechanics in my sophomore year in engineering school, so I know what rocket science looks like. This ain’t it. WTF a bunch of EE’s needed to be force-fed orbital mechanics for, I have no friggin’ clue, but we had to a) buy some hoity-toity idiotic book from the UK (with a powder-puff pink cover, no less) for this course, and b) this book could not be sold back to the bookstore for any amount of money, so I still have the wretched thing. Net:net, I can tell you that it takes a three stage rocket to reach the moon. Not two. Not four. Three. Two or four stages will simply not work.
Making a rifle like a Garand or M14 would be much more difficult. Much, much more difficult. Making an AR? Pfah. This weapon is one step up from making an AK from a poop shovel. The only things on an AR that would be actually difficult to make are a) the bolt and b) the bolt carrier. The barrel extension would be a bit difficult to make, but with some instruction in how to make a broach, it can be done.
Making functional weapons does not require a 3D printer. It does, however, require that some people learn how to work in metal, learn how to weld, learn how to operate a drill press and drive a file (or rather, a bunch of files). If you can drive a file, you can make a gun.
3D printers just make politicians wet their silk panties - because the liberal arts majors in the press and in political office can see how THEY could print out a gun. 3D printing makes things so easy that even some idiot in office in DC could make a gun. THAT scares them... but for real men, who know how to use real tools... guns are easy to make.
Nitrided barrels have better corrosion resistance than chromed barrels. They’re harder too.
Chrome lining is now the bottom of the heap in terms of durability and heat resistance in barrels. Stellite liners are the thing used in heavy machine guns (like M2’s) and nitriding is the new hotness in mil-spec weapons and bleeding edge high power competition rifles.
Chrome is so yesterday.
Ceramic just isn’t going to compete. It’s costly, it’s fragile, it’s hard to work with.
Gun cotton is easily enough made. We can talk of that later.
Barrels:
Making barrels is part science, part witchcraft.
Drilling “deep” holes in a machine shop is one of the most difficult things to do. There are ways to do it on a lathe if you work at slowing down the feed rate to tenths per revolution. Harry Pope used to make barrels on a highly-modified South Bend lathe, so it can and has been done with good success. But when you talk of “deep hole drilling” in machining (where a “deep hole” is > 3 to 5 times the diameter of the hole), you’re into the really high-experience machinist skills - which mot machinists won’t have.
And that’s just drilling and reaming the barrels. We haven’t talked yet of rifling the barrels, which is a whole ‘nuther thing on top of getting a straight, uniform hole.
Now, if we’re talking of 5” pistol barrels, hey, we can do that. An aircraft drill bit that’s undersized, then ream to size, then just ram a rifling button through with an arbor press and you could have a relatively acceptable barrel.
But make a 24” barrel for a rifle in most machine shops? You’d better be looking for the guy in the back of the shop with the foul temper, white (or no) hair, of whom even the owner of the shop is scared. He’s the guy who probably can pull off the job.
For a first time process you could cast the lower out of melted aluminum beer or soda cans. But its not a high strength aluminum allow. Obviously almost any metal would work that can be melted. And anyone can argue themselves blue which is better. But if it fired at least a mag full its a success. Even if its heavy, chunky and full of voids if it houses the important parts and allows them to work then its a success.
The cat is out of the bag, its pregnant and its going to propagate explosively. I visit firearm forums a lot and its amusing how many internet ego experts are popping up claiming it won’t work, it will be ugly, they who make their own are not of the elite bling crowd, yadda yadda yadda.
I see history here when during the Revolutionary war people were making their own rifles, its time we do it again.
Carbon fiber is a bear to work with unless you’re casting woven sheets of the stuff in resin or epoxy like binders.
The first time you get carbon fiber stubble into your flesh from working on carbon fiber, you’ll swear off using the stuff ever again.
Extreme high pressure press compacting sintered metal around a rifled mandrel and simultaneously cooking in a kiln can create a low pressure barrel such for a .45. I am somewhat familiar with the process, can be done with simple 50 ton hydraulic press and a home made kiln. Durability? questionable but would make a Liberty style gun look prehistoric.
You could cast the parts out of beer cans - absolutely true. The only problem in using that particular alloy of aluminum is that it is strain hardened, not heat treatable. FWIW, you can find the same type of alloy in huge, easy quantities by scarfing it off some aluminum siding from a house tear-down, or gutters in the local dump.
There are other alloys which you could find - like the aluminum used in crackcase housings off diesel engines, the pistons off diesel engines, etc. These alloys all exhibit better strength and casting properties than most of the other stuff you could find.
People would do well to think in terms of “Golly, the local auto wrecking yard is positively FILLED with metal... what *is* that metal in there?”
There’s quite a few very useful alloys that are very commonly available in a junk yard - if you know where to look. Axle shafts, transmission gears, pistons, crankcase castings, wheel castings, etc.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.