Nick Bilton writes in the Times about how easy it is to download and print 3D-printed guns, and why this poses a significant threat.

If I had the time, a little technical know-how or was willing to sit through tutorials online, I could buy a three-dimensional printer (which makes objects by spraying thin layers of plastic that become shapes) and print and assemble some of these guns.

Among the files now sitting on my laptop are parts for an M16, AR-15, AK-47 and other semiautomatic guns. There are files for handguns, including a Glock, Beretta and a .22-caliber Ruger.

It took me about five minutes to find these gun schematics online. A teenager who grew up on the Internet could probably find them in half that time.

It is quite easy to find the blueprints online, no doubt. But actually printing a functional gun takes quite a lot of expertise and know-how. As I discuss in my article on 3D Printing and the Second Amendment, actually creating a workable 3D-printed gun is a lot harder than its worth. It is almost always going to be easier to find a readily available real gun somewhere. Bilton observes that even a single-shot gun is dangerous.

Gun lobbyists argue that 3-D printed guns are pointless because many of these weapons can be fired only a few times before the gun breaks, often overheating and cracking. But last I checked, one shot is enough to kill someone. (The Reprringer is based on the design of the derringer pistol, which killed President Lincoln.)

Well, yeah. It is really, really easy to make a homemade gun from parts available at any hardware store, that are not made out of metal.

This video on YouTube shows an improvised shotgun, which consists of two pieces of walled tubing, a nail, and a shotgun shell. It cost $7 of materials and took little time to make–much less time than a 3D gun. It is quite lethal, and will likely not set off a metal-detector. (Of course even with a plastic gun, bullets are made out of metal).

If young dumb kids wants to make an improvised explosive, they don’t need a 3D printer.

Bilton explains that these 3D guns are a problem:

“Weapons experts will tell you these guns are a joke and not that serious,” said Hod Lipson, director of the Cornell University Creative Machines Lab. “But that’s exactly the problem. Plastic guns are easy to fabricate, they can be used just a few times and you can make guns that don’t look like guns.”

What’s more, he noted, these weapons are very difficult to detect at security points, as they often don’t have metal parts or, if they do, just a spring and a couple of screws, all of which could easily pass through a metal detector.

Mr. Lipson, who is an author of the book “Fabricated: The New World of 3D Printing,” said the public should worry not so much about these weapons falling into the hands of terrorists or hardened criminals, who already have access to most any weapon they desire. “The real danger is kids and teenagers and hobbyists who will attempt to make these,” he said.

Bilton also alludes to one possible solution–companies that make 3D printers should block certain designs:

But it seems that the 3-D printing companies are the only ones in this equation that could offer some protection against the proliferation of 3-D printed guns, especially when it comes to children who may try to make them. These companies could ensure that 3-D printers can’t print certain parts, or can only access approved websites to download files.

But instead, most 3-D printing companies I reached out to did not respond to a request for comment. MakerBot simply referred me to their “terms of service” disclaimer, which prohibits sharing weapons files on their website.

Inserting DRM-style filters into 3D printers would be a very bad first step. More likely than not, through what I describe as a Baptist and Bootlegger coalition, media companies who seek to insert IP-style filters into the printers will ride the 3D-gun wave.

“[C]ompanies with a vested interest in the current system must not be allowed to use concerns about homemade guns or other distractions as an excuse to shackle 3D printing.” There is always the risk of a Baptist and Bootlegger coalition forming. Manufacturers who seek to shut down 3D-printing will ride the wave of opposition to 3D guns to stifle this innovative industry. Desai and Magliocca conclude that “[t]he understandable desire to prevent individuals from making untraceable or illegal guns should not cause undue alarm.”

I will be giving several talks on 3D guns at campuses across the country. Stay tuned.