Locklin on science

Bad engineering journalism: reporting on “3-d printing of guns”

Posted in Design by Scott Locklin on August 11, 2012

Everyone and his brother is reposting one of the many articles on the guy who used a 3-d printer to build an AR-15 lower receiver. They’re making it seem like this is important, because pretty soon you will be able to use a rep-rap to print up an AR-15. This isn’t stats-jackassery, but it is the most pig-ignorant engineering jackassery I’ve seen in some time.

The Wired article  isn’t bad, and it doesn’t tell any obvious lies beyond the title and Brady center nonsense, but it leaves you with the impression that 3-d printed assault rifles are just around the corner. No, this is not possible. This will never be possible with 3-d printing technology; not now, not any permutation of it in the future. The guy who did this trick said as much himself; the media frenzy over this is ridiculous. He’s performing a silly engineering trick, not pushing technology forward. Some of the other stuff written about this demonstrated criminal neglect of fact. There should be a professional penalty for journalism as bad as displayed in the Business Insider article, beyond my calling the author out as a gibbering ignoramus, but alas, there is no other penalty for telling hysterical lies in public.

The AR is one of the few rifle designs where you could even think about using a lower receiver made out of plastic. It is also one of the few rifle designs where the lower receiver is legally considered “the gun” by the ATF. In other nations (like, I think, Canada), the upper receiver of the AR-15 is legally the gun, and a plastic version would melt if it didn’t dissolve from mechanical stress the first time you fired it. Sane people build their AR lower receivers out of aluminum or steel (there are a few composite ones on the market using advanced lightweight materials). Less sane people whittle them out of pieces of wood, just to show that it can be done.  Since the creator of this object isn’t suicidal, he’s not even using the .223 Remington ammo typically used in AR-15 style guns; he’s using .22 Rimfire, which is ammo with about 1/10 of the already relatively low muzzle energy of .223 Remington. Virtually all of the important parts of this project are manufactured from metal by professional gun makers, and they always will be.

Here’s a picture of the AR lower receiver he’s printed:

The first thing you’ll notice; this is not a solid object. It’s a bunch of thin layers of plastic more or less stuck together. This is something you  always notice when you handle solid printer output, but particularly the egregiously bad output of home solid printers. It’s badly made; barely a solid at all.  The second thing you should notice is the little red arrows, pointing towards the crack when he tried to drive a necessary pin through the thing. It disintegrated along a predictable fault line like the piece of layered plastic junk it is. He fixed it using glue. FWIIW, you could build a lower receiver out of epoxy using hand tools, and it would be a lot stronger. It would still be a dangerous piece of junk, it would be significantly less dangerous to the operator than this contraption, because set epoxy is an actual solid.

Another picture:

Oh look, a shiny piece of aluminum. One which he machined on his lathe. Screwed into the “receiver.” This is necessary, because the plastic isn’t enough to protect the user in case the locking mechanism fails. He also needed to machine his plastic receiver once it was printed, with hand files, drills and some extra bits of glue to hold it together. Hardly a print and play operation here. If he just wanted to make a working gun out of a barrel and bolt, he could have done so with duct tape, modeling clay and superglue.

Note also, that you could build most parts for virtually any kind of gun if you have a $200 lathe (and some tooling) in your house, which this guy already has. It would probably be less trouble than this project, and it would certainly be safer for the operator. Some kinds of submachine guns can be made out of muffler tube and a hacksaw if you have the barrel and trigger group. The British invented their Sten gun to be this way, so the resistance in occupied Europe could hose the Nazis down with hot lead. Guns are easy to make. There are cottage industries for doing so with hand tools in the wild places of the world.

As I noted above; he could have done this using plastic or even bits of pine wood, and it would work better. People have; check the links. Why don’t people freak out over that?

I think the reason people freak out over this is the  unreasonable enthusiasm for solid printers. I’ve used the output of early high-end solid printers, all of which are far superior to hobbyist garbage like the “rep-rap.” They’re useful for making plastic parts for prototyping purposes. A firm I worked for in 2000 used this tech to make a dummy iphone (which hadn’t been invented yet: we were ahead of the curve) to mount accelerometers to. That’s the kind of thing solid printers are useful for. The hobbyist hysteria over 3-d printers is unwarranted.  Serious people who want to make useful objects, like, I dunno, the humble screw, will make them out of metal using machine tools and casting, and maybe use a solid printer for difficult to machine plastic parts. Difficult to machine plastic parts are pretty optional when constructing useful devices; usually the solid printed part ends up being something like a plastic box (which is effectively what this lower receiver is; a box with some holes in it). In ye olden days, the box would be made out of wood, which is stronger and looks better, and can be made without some dope fiddling on a computer.

Nerds have this fantasy that solid printers will make them infinite open-source useful objects in … the future. This is the sheerest fantasy; a fantasy that can only be held by people who have never made a useful  mechanical object in the workshop. Solid printers can make crude unassembled plastic parts; nothing else. No electronics can be made in this way. No assembled parts can be made in this way. Even if a home printer could print things of metal (this will never happen on a cheap home use basis as you need a very high power laser to melt metal powders), it will effectively be sintered metal, or sintered plastic-metal composites. That’s not the same thing as a machined piece of solid metal. It doesn’t have the same mechanical properties, and barring some preposterous breakthrough, it never will. Some parts will not ever be realizable with this sort of technology: for things like, say, a plastic simulacrum of a rifle barrel within linear tolerances, you’ll always need specialized machine tools. Not that machine tools are terribly difficult to obtain or use. Hobbyist CNC (aka computer controlled machining) tools have been around for decades, and they’ve hardly amounted to “home printing of useful objects.”  The CAD design for this plastic lower comes from a CNC design which has been freely available online for at least 10 years now. Since solid printer nerd enthusiasm outnumbers CNC nerd enthusiasm by many orders of magnitude, nobody made a fuss over that. Anyone who thinks solid-printing is awesome should get on a lathe and figure out how real objects are made before they yap about rep-rap. It’s fun. I learned how to do it as an undergraduate, and keep an Austrian clockmaker’s lathe in my kitchen for when the mood strikes.

The guy who did this should be applauded for his engineering cleverness and brass testicularity in attempting to fire such a dangerous-to-the-user object. The doltish journalists who wrote breathless articles about  it should mocked for their hoplophobia and ludicrous ignorance of the most rudimentary engineering knowledge.

49 Responses

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  1. prcaldude@gmail.com said, on August 11, 2012 at 3:09 am

    Fools like John Robb promote this technology all the time.

    I tried machining some simple parts one time in the company shop and it was really hard and beyond the abilities of most people.

    • Scott Locklin said, on August 11, 2012 at 11:55 pm

      Machine work is something where a course of some kind is definitely useful. Lots of tricks of the trade, and not many books to tell you how to do it.

  2. Rod Carvalho said, on August 11, 2012 at 11:47 am

    My impression is that 3D Printing is nothing more than low-cost Rapid Prototyping (RP) for hobbyists. Am I correct? What exactly is new about 3D printers? RP has been around for at least two decades. Am I missing anything obvious?

    BTW, do admire the hype machine in Neil Gershenfeld’s TED talk on “Fab Labs”.

    • Scott Locklin said, on August 11, 2012 at 11:54 pm

      I guess there are very cheap solid printers now. BFD; they produce very shitty output. Somehow “rep rap” is given credit for being “self creating” because it can make a couple of it’s own parts. They’re not very interesting parts.

      • prcaldude@gmail.com said, on August 12, 2012 at 2:21 am

        These people like to say that people like us were saying the same thing about desktop computers during the days of mainframes. Of course, computing power increased exponentially in a few decades while this technology has jogged in place.

        • Scott Locklin said, on August 13, 2012 at 1:23 am

          That is one of those false analogies that is deployed everywhere; from “nanotech,” to “AI,” to, well, take your pick. Some stuff improves exponentially. Some stuff improves linearly. Some stuff improves logarithmically. Some stuff doesn’t improve at all, or devolves. Some stuff is science fiction that hasn’t been invented yet. And of course, nothing improves forever.

  3. Stanislav Datskovskiy said, on August 12, 2012 at 3:56 pm

    When you see something like this, the possibility of the media hysteria being *orchestrated* is at least worth considering. Right now, you can buy every other part of an AR-15 online without any official paperwork, in all 50 states. The gun-grabbers don’t like this one bit. Expect the loophole to be closed in the near future, one way or another. 3D-printed receivers are just an excuse. If they did not exist, another excuse would be found.

    I predict that 3D printers themselves will also be banned (or otherwise laden with bureaucracy) in the unlikely event that they ever show any signs of being improvable into actual usefulness at producing everyday objects. To our rulers, scarcity is the holiest of holies. (Though it is in no danger whatsoever at our present tech level.) They would rather take no chances.

    • Scott Locklin said, on August 13, 2012 at 1:17 am

      Malice and stupidity and all that. Home CNC machinists have been making these things for at least a decade, out of proper materials like aluminum.

      I’m sure if solid printers become useful, the solution will be something along the lines of how the manufacturers get paid in selling cheap inkjets. Make the feedstock expensive: problem solved. I suspect it is already expensive.

      • Stanislav Datskovskiy said, on August 13, 2012 at 1:31 am

        But what probably won’t be allowed to happen is any risk of a transition from “CNC machinists” to “any old idiot with an Internet connection and a few hundred bucks.” Which, as you clearly explained, is in no actual danger of happening in this case. But notice what happened to hobby chemistry sometime between 1960 and the present time. The police state does not sleep, and the list of equipment and raw materials forbidden to the plebes “just in case” grows ever longer and longer.

        • Scott Locklin said, on August 13, 2012 at 1:43 am

          You are certainly right about this example. I was recently looking for a chemistry set for a friend who was denied one in her youth. Apparently, all the interesting chemicals can be made into … I dunno what, and so you have to acquire them from household chemicals to make the “set” work. I don’t know what the rationale for this is, but the chemistry set is now dead, and this is a terrible crime against common sense and future generations of young scientists. Meanwhile, little kids can buy horrifically dangerous “bath salts” and wacky fake-pot in a freaking gas station. Anarcho-tyrrany.

          • Stanislav Datskovskiy said, on August 15, 2012 at 12:59 am

            If you think about it, chemistry sets (as opposed to hobby chemistry in general) were killed by the fear of liability lawsuits rather than the War on Drugs. That no one stood up to defend them is merely another symptom of sclerotic cultural decay, rather than a cause.

            The worship of “safety” above all else comes from the unspoken assumption that risks no longer need to be taken, that we should simply coast along on the successful risk-taking of our ancestors forever. The fact that doing so is a massive risk in itself (quite like stepping in front of a moving bus; the word “risk” is almost laughably inadequate here) is lost on the pampered suburban poodles. The latter are quite ineducable; even now as the Collapse is in full swing, they attribute their misfortunes to “bad luck.”

            Notice the eagerness with which the “TED talk-listening” crowd latches on to any, even the most transparently pseudoscientific talk of a scientific breakthrough that promises to stave off the inevitable. Somehow, “Progress” is supposed to “just happen”, without having anything to do with curious children being allowed to even occasionally play with strong acids or open flames. Discoveries are now expected to come from Certified Professional Discoverers, who dutifully did their homework for twenty years of Confucian schooling (or dutifully fellated their advisors, in the case of the actual Confucians.)

            I fully expect amateur electronics-diddling to suffer the fate of amateur chemistry. The only questions are: when; and what sort of bugaboo excuses will be brought into play to make it happen. DRM-cracking, cellular jamming, or the very same 3D printing come to mind. If you don’t presently own a logic analyser, consider purchasing one before they become subject to the same official scrutiny as pill presses.

            • Scott Locklin said, on August 15, 2012 at 1:16 am

              I think this has already happened to a certain extent. The DRM guys certainly make things difficult for the open source crowd. The only check is … the open source crowd has rich sponsors at google and such.

              I think you’ve locked onto something important. Complainers change things. Nobody else notices, or they simply go along with it “for the chilluns” or whatever. Things get worse. It’s a sort of unstoppable “rent seeking” behavior in a social democracy. The founding fathers more or less warned about factionalism and special interest groups, but it’s too much work to keep track of all the do-gooder assholes who are ruining civilization for everyone else. I want my phucking Lawn Darts!

  4. 1RW said, on August 18, 2012 at 3:57 pm

    Dear Scott, I must respectfully disagree with your outlook on 3d printing. While I agree that making guns out of 3d printed parts is more engineering screwing around than useful work, 3d printing is used for actual production parts. The things I know of
    – Laser Sintered (LS) Nylon air ducts for the FA-18
    – LS Peek hot air ducts for F-35 (yeah, I know it’s a turkey, it still has high grade aerospace stuff inside)
    – Unknown 3-d printed material used for UAV fuel tanks, (coated with a polymer to prevent fuel absorbtion by material)

    Finally, I personally use 3d printed stuff at work because
    – Cost is competitve with machined metal parts
    – Lead time is typically much less
    – Printed object cost scales with object envelope volume. Machined object cost scales with the number of operations. As your geometry becomes complex, machining cost grows, printing stays the same.
    -Sometimes it’s cost effective to print a part and then do some machining on it afterwards to bring critical features into tolerance
    – I’ve had complete mechanisms printed wholesale out of LS Nylon (a base with some clamps on it) Each unit came in at ~$100. Equivalent functionality from COTS metal stuff would have been ~$180, with 6 times the individual solid objects.

    Of course, any material including metal has limitations, and the engineer must be cognisant of those when designing parts. 3d printed parts aren’t as strong and tough as metal. But a lot of useful objects do not need to be super strong. If strength is an issue, a part can be made bigger, with thicker walls. However, good luck machining a 3d manifold with ducts that don’t have sharp corners. Or a fuel tank that exactly fits around all the internal components to maximize useful volume. Or a fuel tank that has a manifold as part of its structure.

    PS – the feedstock is expensive, but so are the machines

    • Scott Locklin said, on August 21, 2012 at 8:22 pm

      I don’t disagree with any of this, but laser sintering is a different process than was used to create the receiver described above. I’m almost positive that hobbyist class 3-d printing is extrusion; essentially a hot-melt glue gun on an inkjet printer x-y axis controller. At least I didn’t notice any CO2 lasers on the rep-rap I looked at.
      Certainly you get cheap plastic parts for high end projects that way. For one-offs or short runs, laser sintering is probably a lot more cost effective than blow molding or whatever they’d use otherwise. Not exactly a revolution in democratic manufacturing, as it is pitched, however.

  5. neutrino_cannon said, on August 22, 2012 at 2:49 pm

    As someone who briefly worked at a “reprap” hobbyist 3D printer assembler and sales outlet, I agree. This looks exactly like it was made with an ABS extruder printer.

  6. prcaldude@gmail.com said, on August 23, 2012 at 8:19 pm

    Paging Mr. Locklin….:

    Hey, at least this technology began in the private sector. If this article began, “Researchers at ___ university….,” we’d know for sure this technology was a dead-end.

    • Scott Locklin said, on August 23, 2012 at 8:30 pm

      While I’m inclined to short anything said in “New Scientist,” I figure making stuff out of wood pulp has a long history and a bright future. Main question I have about this stuff, “what happens when it gets wet?” If something bad happens, this is probably not the next big thing.

  7. asciilifeform said, on January 9, 2013 at 12:31 am

    An update re: the typical failure modes of 3D-printed plastic AR lowers: http://defdist.tumblr.com/post/38814117440/christmas-review

  8. […] Bad engineering journalism: reporting on “3D printing of guns” – Scott Locklin […]

  9. […] and embarrassed by their lack of interaction with the real world. This is how stupid  ideas like solid printing get traction. Keyboard warriors want to work in meatspace, but they don’t know how. For a […]

  10. Michael said, on February 13, 2013 at 6:30 pm

    Sintered metal is a reality as they are making finished for the end user parts right now.

    They could make a complete ready to use AR15 lower that would only need a little cleaning/polishing up, but you would need more than $100,000 to purchase the machine to do it with.

    • Scott Locklin said, on February 13, 2013 at 9:09 pm

      Great: for $100k, you can buy a machine which makes a $5 part. One you could make on a $1000 machine that would also be able to make a barrel. For $100,000 I could buy a Mig-21 with 23mm cannon in it.

      • Michael said, on February 14, 2013 at 2:54 pm

        No, it just does not make only one $5 part.
        You could make an AR 15 lower in one step that a machine shop would have to order the forging, mill on one side, turn over, mill the other side, machine out a pocket, then broach (or EDM), then drill holes from this angle, then that angle, thread some of them, then machine this, then machine that taking all day to get to a finished part. then send it out to be polished and deburred.
        3D printing you can print the finished part in 5 minutes only needing to be polished to make it pretty.

        • Scott Locklin said, on February 14, 2013 at 9:26 pm

          The 3D printed AR-15 lower will in fact, need half of those processes done to it as well, and when you’re done, it will be a piece of sintered garbage. There is a reason people don’t sell sintered AR-15 lowers; because it’s garbage. Have you ever done 3-d printing? Have you ever done machining of any kind? It doesn’t take all day to make an AR-15 lower. I linked to an example above where someone made one out of a piece of plywood in a few minutes.

          You also can’t make the most important parts of the gun: the barrel and bolt, using this technology, which makes it moronic applied to objects like guns, even if those parts are not registered as guns in America at present. Machine tools work better. They’ll always work better. 3D printing will always be a manufacturing adjunct, and no it won’t change anything.

          • Michael said, on February 14, 2013 at 9:43 pm

            Back in the beginning, yes, it looked like crap, but what they are cranking out these days is of a much higher quality.

            And I did mention polishing the exposed surfaces as they are a little rough.

            And yes, I have “done Machining” and as far as that plywood link you provided Scott, VERY PROFESSIONAL LOOKING WORK DONE THERE.

            Obviously much better than anything modern Direct Metal Laser Sintering could ever produce (Please note the SARCASIM).

            • Scott Locklin said, on February 14, 2013 at 9:54 pm

              OK, tell me, how much does it cost in feedstock and power to build a shoddy $5 part with a $100k machine you’ll never be able to fit in your house, and that still can’t make the important parts of the gun?
              You do see what this article is about, right? The solid printing of guns and gun parts. The thing freaking out legions of policy idiots, and causing libertards to swoon. The thing that isn’t even really possible in any way. When you can make your laser sinterer relevant to that subject, you can continue making sarcastic noises.

              • Michael said, on February 14, 2013 at 10:19 pm

                Hey genius (Note additional sarcasm), have you ever seen the first powered vehicles ever made?

                Steal powered and weighed several tons and barely crawled along.

                look at modern tractors today!

                Compare vinyl records, that became 8 tracks, that morphed into cassette tapes, that again changed into CD’s that is now a tiny little Gigabyte stick.

                3D metal might today be $100,000 machines the size of a large cabinet, but wait a few years and they will speed up, the quality will refine to smaller and smaller tolerances and the unit size will shrink drastically.

                the future is coming and there is nothing you can say that will stop it.

                I see there were others that have rebutted your various comments and it seems that “Scott Locklin” is just looking to vent and bash the technology to anyone willing to respond.

                Give it up Scott and go back to your soon to be antiquated technology and leave the future to those of us with vision.

                As far as I am conserned, you are done.

                Turning off the email notification.

                • Scott Locklin said, on February 14, 2013 at 10:31 pm

                  “3D metal might today be $100,000 machines the size of a large cabinet, but wait a few years and they will speed up, the quality will refine to smaller and smaller tolerances and the unit size will shrink drastically.”

                  “3-d metal” printing involves MELTING METAL, dummkopf. With a fucking laser; you know, the gizmos that have enormous inefficiencies in converting electricity into a beam of heat. That’s why I asked you how much feedstock and energy it takes to make a $5 part. I’ll cue you in: it’s more than $5. Also: show me a sintered barrel while you’re at it. In fact, why don’t you try shooting one? Preferably in 338.

                  Since you’re unable to notice the most basic of facts about this over hyped technology, or, like, address the fact that guns have barrels and bolts, well, don’t let the door hit you in the ass! Also, please learn to spell. People who spell are generally trusted more when it comes to prognostications on over hyped technologies.

                  • Michael said, on February 14, 2013 at 10:49 pm

                    Whine, cry, bitch, moan and complain, you are still an idiot nobody.

                    And you obviously did not read my comment on barrels jack ass.

                    Come on out to this part of Illinois and perhaps we could meet for….let’s call it coffee?

                    • Michael said, on February 14, 2013 at 10:51 pm

                      A bad Journalist reporting on bad engineering!!!
                      Thats funny!!!!

  11. William Ashley said, on February 23, 2013 at 8:50 am

    I would suppose if small enough scale a sintered weave would offer strong material strength. Like using a fractals designed weave to propel the stress to the end of the barrel from the chamber. I think using this process as opposed to casting you could get a much better strength.. I also wonder what would happened if you tempered the object after through recasting and quenching… like heating it with a superheating coil passthrough to heat the metal to its bonding threshold , then also pulse it with an electromagnetic pulse to align its atomic-molecular properties – then the quench to give it a good strong kick- Seems the sintering could be a fist stage.. while recasting and quenching could be used =- perhps with carbon to increased the hardness.

  12. William Ashley said, on February 23, 2013 at 8:58 am

    super heating coil = induction heater

  13. Michael said, on February 27, 2013 at 1:30 pm

    Well said William Ashley.

    I do believe that the finished condition of a laser metal sintered part is that it only has an issue with the surface texture not being smooth.
    The strength is the same as if it were cast as one piece.

    • Scott Locklin said, on February 27, 2013 at 8:05 pm

      Meanwhile, you could have machined the part out of high strength aircraft aluminum in the time it took him to write that (which is wrong, BTW), and the tooling is cheaper.

      • Michael said, on February 27, 2013 at 10:59 pm

        This is getting fun.

        There are things you can do with a 3D printer that CAN’T BE DONE BY CONVENTIONAL MACHINING!

        And, NO WAY you can know if a part can be machined as fast as printed until you know how fast the printed part is and how complex the design, how many steps it will take, and how many fixtures you will need for each step.

        And as for tooling, other than cleaning up the surface (just like the rough surface of the “high strength aircraft aluminum” machined part) there are no tools to wear out (you do know CNC mills and lathes, broaching machines as well as EDM machines all have to be readjusted, for EACH time a tool is replaced.

        BYW SCOTT, any type of metal, even your “high strength aircraft aluminum” can be delivered in powder form.
        they even use TITANIUM, OOOOOOOH!

        Scott Knucklehead, you remind me of those Engineers that have no clue why something is difficult, or impossible to do, or have no clue why what they designed will not work well because they never turned a wrench.

        I’m not the only mechanic who had to redesign some of the CRAP they design.

        • Scott Locklin said, on February 28, 2013 at 2:09 am

          There are many more things that can be done by conventional machining that cannot be done by 3D printing. One of the more pertinent ones is making a rifled barrel. Go ahead and prove me wrong by making one. There is no time limit, until you die, in which case, “time’s up!”

          There is a way I can know this: I have used both techniques, along with EDM. I’m well aware of the problems with these forms of fabrication, and many more of the idiotic process you seem to uncritically accept as being a magic toaster capable of making your heart’s desire. How long have people been trying to make a shitty AR lower, a glorified plastic box, and failing at it? How long did it take the dude to make one of bondo and popsicle sticks … one that works better?

          Yes, asshat, powder is wonderful for constructing solid objects from. When you tell me where the heat source for melting it comes from, and how much it costs compared, to like spinning a sharp cutter, you might have a point. Meanwhile, you’re a credulous numskull who has never constructed a solid object made out of matter more complex than your lunchtime baloney sandwich.

          • Michael said, on March 1, 2013 at 5:01 pm

            Well “Mr asshat” AKA Scott Locklin, I did not say anything and everything can be built, I mentioned an AR15 lower, that is all, not a broached barrel.

            And some machining steps for certain types of procedures will need to be done in a certain way, but if you take a minute and research WHAT THEY ARE DOING NOW, you will see things being done that could never be done with conventional machining.

            Some day they will be able to 3D print a perfect barrel with rifling and all, not now, but some day.

            The technology is moving forward and all you want to do is shovel negativity and name call anyone who does not agree with you.

            Way to show your level of professionalism Scott.

            • Michael said, on March 1, 2013 at 5:09 pm

              I encourage and respect substantive disagreement, however, if you say something dumb or merely disrespectful, you may get this in reply.

              The link to “THIS” is dead due to 3rd party infringement.


              You “encourage and respect substantive disagreement”?

              It does not seem like it.

              “Meanwhile, you’re a credulous numskull who has never constructed a solid object made out of matter more complex than your lunchtime baloney sandwich.”

              How old are you Scott?

              Does your mommy know you are on line???

              • Scott Locklin said, on March 1, 2013 at 6:43 pm

                Maybe you should look up the word “substantive” for a start, followed by “dumb” and “disrespectful?”

            • Scott Locklin said, on March 1, 2013 at 6:53 pm

              Dr. Asshat to you, Chumley. I’m well aware of WHAT THEY ARE DOING NOW. I’m not impressed. That’s why I write about crap like this: that and because knuckleheads like you have hyped a marginally useful technology beyond all reason. That’s what gets attention and funding today: hype, exaggeration and total bullshit.
              I blame too much democracy; when people who don’t know what they’re talking about, and don’t even feel like, you know, learning what they’re talking about, feel entitled to a technical opinion, you get mountebanks and hype on bullshit instead of new technology. Have fun picking potatoes with your solid printed coffee cup powered Stirling engine iphone recharger in the new dark age.

              • S. Adams said, on March 10, 2013 at 4:25 pm

                I was kinda hoping the argument would continue here. It’s pretty amusing watching Michael show his real age and dodge the questions about barrel and bolt manufacture. Or the cost of laser sintering anything. The straw-man attacks are pretty hilarious too.

                Don’t get me wrong, I think printed parts could be pretty nifty, but I’m a bit skeptical about anything that’s made completely of plastic. Probably because I spent too much time giggling with a blowtorch and toy soldiers as a child. Or maybe because the job I do depends on having a very sturdy hull between me and a potentially very large boom.

                • Michael said, on March 11, 2013 at 5:28 am

                  “knuckleheads like you have hyped a marginally useful technology beyond all reason —- hype, exaggeration and total bullshit”

                  This statement shows you are not up to date as they have been making Laser Sintered Metal parts for quite a few applications for quite a while now.

                  If anything is marginally useful, it’s you, a self professed “former” physicist, and this blog you seem to live for, along with a level of NAME CALLING and trash talk that puts into question not only your education but your upbringing as well.

                  And S. Adams, I did not “dodge the questions about barrel and bolt manufacture” as I stated in the beginning I was only talking about the upper and lower housing, thats all.
                  I never mentioned that, but Locklin made the assumption and then shot off his mouth with talking trash and name calling.
                  However I am 100 % Certain that every single part (a plastic part replicated in 3D printed plastic or metal part replicated in 3D printed metal) can be made for the AR 15 by and or sintered laser technology *with the exception of the Bolt, Cartridge Extractor,Barrel, Barrel Spacer and springs* only because the pressures they experience (as far as we know today) have not been tested with a Sintered part as of yet.

                  I am also unaware of any Sintered Laser Metal springs being made and what their overall quality will be like.

                  Until they make those parts and pressure/function test them, you can’t say it will not work, and I can’t say that they will, but as I said before, the technology is moving forward.

                  “Have fun picking potatoes with your solid printed coffee cup powered Stirling engine iphone recharger in the new dark age.”
                  And I have no idea how this comment about a “coffee cup sterling engine I-phone recharger” comment is relevant in any way to this discussion.

                  • Scott Locklin said, on March 11, 2013 at 9:49 pm

                    Again: you’re using a giant, energy hungry machine that will never be available to consumers to make non-critical parts that are more easily and cheaply made in any of a dozen other ways. Why should I give a shit? Why should anyone give a shit?
                    All the government need do is make the bolt or barrel legally considered a gun, and your dumb idea becomes even more irrelevant than it already is. Meanwhile, nobody has made a solid printed AR lower which beats a piece of plywood and some bondo.

                    • Michael said, on March 11, 2013 at 11:38 pm

                      Rapidly manufacture fully dense
                      end-use metal parts.

                      The laser they used is rather small and focused, and if you will just take a look at the end of this post and you will see.
                      Compared to all the energy used to forge, transport the forging to the machine shop that will mill, drill, broach and thread only to be sent out to be cleaned and coated.
                      How about all the invested energy in the ongoing needs of tooling and the maintenance, and replacement of those tools when they become worn or the cutting edges become dull?
                      How about fixtures?
                      Laser sintered metal can either go from printing right to the cleaning and coating steps, or with the right process, printing to end use.

                      Milling, drilling, broaching and threading steps will not be needed as seen below.


                      MicroFine Metal is the newest technology of our high-quality, precision rapid prototyping services. Exclusively from FineLine, full-strength metal parts can now be produced with the same ease and speed as plastic parts. These production-quality prototypes can be built in stainless steel and aluminum. More specifically, the following materials are available as part of our MicroFine Metal service offering:
                      MicroFine Metal Direct:
                      Stainless Steel 17-4PH
                      Stainless Steel 316L
                      MicroFine Metal Casting:
                      Aluminum 6061-T6 (A356.2-T6)
                      Aluminum 2024-T7 (B206.2-T7)
                      MicroFine Metal parts are built in micro-resolution (.001” layers), making extremely fine details possible.
                      The MicroFine Metal Direct process has a working build envelope of 3.5” by 3.5” by 3”. The process is capable of resolving features down to .005”. Tolerances of +/-.002” or better can be expected on features under 1”. Surface finish of the parts as built is approximately 130 microinches RMS.

                      Another one.


                      sPro™ 125 Direct Metal
                      SLM Production Printer
                      Rapidly manufacture fully dense end-use metal parts up to 125 mm (4.92 in) in length with excellent surface finish, feature detail and tolerances with this state-of-the art manufacturing system. Choose from a large range of metal alloys, including aluminum and titanium.
                      Applications include functional testing of production-quality prototypes, and organic or highly complex geometries. Other examples of rapid low-volume manufacturing of metal parts are: custom medical implants, lightweight aerospace and motorsports parts, efficient heat sinks, injection mold inserts with conformal cooling channels and dental caps, crowns and bridges.

                      opening up the Direct Metal (SLM) Family Brochure and Technical Specifications (.pdf) for some specifications.

                      And as for giant energy hungry lasers eating up all that energy?

                      The PDF list the pro 125 as only using a 208V 3PH, 30A, 60Hz or localized via transformer using either a 100 watt or a 200 watt laser.

                      The PDF also list the pro 250 as using a 208V 3PH, 30A, 60Hz or localized via transformer using either a 200 watt or a 400 watt laser.

                      And as for huge.
                      The 125 unit is 53L x 31.5W x 75H inches and weighs 1984 lbs.
                      The 250 unit is 67L x 31.5W x 80H inches and weighs 2425 lbs.

                      Hell, I could stuff the smaller one in a mini van and bring it home!

                      I have no doubt it would not matter if someone out there printed an AR15, shot it successfully with a high pressure test round and then smacked you over the head with it and knocked you on your inflated egotistical ass you would still keep your limited, small minded attitude.

                    • Scott Locklin said, on March 12, 2013 at 12:37 am

                      So, what you’re telling me is, if you had a gizmo the size of an RV, which requires extremely expensive feedstock, costs somewhere between a million and a million and a half dollars, which requires tens of kilowatts to operate, which literally weighs a ton, and which can make objects a mere 5cm^3 an hour (burning tens of kilowatts all the while), you could make something to almost as good a tolerance, with significantly worse mechanical properties as I could make on my 85 watt, 12lb Unimat-III combo lathe/endmill out of a solid piece of metal with a few cuts and drill holes?

                      Congratulations: you are an idiot.

                      BTW, the tiny little Unimat, which cost me $300, can make larger parts than the 3″ long capacities of the former, and the 4.92″ capacity of the latter machine. I have turned stainless, titanium and drill rod on it; meaning it’s theoretically quite capable of bolts and barrels as well, though it isn’t big enough to make an NFA compliant rifle barrel. For 500 bucks, I could pick up a cheapie at Harbor Freight which would do the trick with a little work.

  14. […] Controversially, people are also experimenting with printing gun parts. The lower receiver for the AR-15 has been printed and they have been able to fire off a couple rounds. However, with the groundswell of imagination and attention about 3D printers by the public, national tragedies in gun deaths, and gun control laws under review, this makes for one aspect of 3D printing that has much attention. However, in reality, being able to print fully functional guns is not easy, and will still take years to figure out. […]

  15. Richard said, on December 11, 2013 at 1:40 am

    Here, you can print cheaply with metal. This is without any optimization.
    I find it much easier to design parts on the computer and then print them as opposed to machining by hand.

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