I noted earlier that you can make a pretty dangerous Gauss rifle using a few easily available and legal components, and you could make a 3D-printed jig to arrange them for maximum effect. So I suggested that maybe magnets should be banned too.
(Incidentally, the toy ones you see on YouTube etc. typically just use a few magnets and some regular steel balls. Using large Nd magnets throughout with the positions and polarities optimally set would make it much more powerful).
Now I learn that a US senator (Leland Yee of San Francisco), HT Dave Evans for the link http://t.co/REt2o9nF4t, wants 3D printers to be regulated somehow, in case they are used to make guns. That won’t reduce violence if you can easily acquire or make lethal weapons that are perfectly legal without one. On the ground, even highly lethal kitchen knives and many sharp tools aren’t licensed. Even narrowing it down to planes, there is quite a long list of potentially dangerous things you are still very welcome to take on board and are totally legal, some of which would be very hard to ban, so perhaps we should concentrate more on defence and catching those who wish us harm.
Here are some perfectly legal weapons that people carry frequently with many perfectly benign uses:
Your fingers. Fingernails particularly can inflict pain and give a deep scratch, but some people can blind or even kill others with their bare hands;
Sharp pencils or pencils and a sharpener; pens are harder still and can be pretty sharp too;
Hard plastic drink stirrers, 15cm long, that can be sharpened using a pencil sharpener; they often give you these on the flight so you don’t even have to bring them; hard plastics can be almost as dangerous as metals, so it is hard to see why nail files are banned and drinks stirrers and plastic knives aren’t;
CDs or DVDs, which can be easily broken to make sharp blades; I met a Swedish ex-captain once who said he always took one on board in his jacket pocket, just in case he needed to tackle a terrorist.
Your glasses. You can even take extra pairs if the ones you’re wearing are needed for you to see properly. Nobody checks the lenses to make sure the glass isn’t etched for custom breaking patterns, or whether the lenses can be popped out, with razor-sharp edges. They also don’t check that the ends of the arms don’t slide off. I’m sure Q could do a lot with a pair of glasses.
Rubber bands, can be used to make catapults or power other projectile weapons, and many can be combined to scale up the force;
Paperclips, some of which are pretty large and thick wire;
Nylon cord, which can be used dangerously in many ways. Nylon paracord can support half a ton but be woven into nice little bracelets, or shoelaces for that matter. Thin nylon cord is an excellent cutting tool.
Plastic zip ties (cable ties), the longer ones especially can be lethally used.
Plastic bags too can be used lethally.
All of these are perfectly legal but can be dangerous in the wrong hands. I am sure you can think of many others.
Amusingly, given the Senator’s proposed legislation, you could currently probably take on board a compact 3d printer to print any sharps you want, or a Liberator if you have one of the templates, and I rather expect many terrorist groups have a copy – and sometimes business class seats helpfully have an electrical power supply. I expect you might draw attention if you used one though.
There are lots of ways of storing energy to be released suddenly, a key requirement in many weapons. Springs are pretty good at that job. Many devices we use everyday like staple guns rely on springs that are compressed and then suddenly release all their force and energy when the mechanism passes a trigger point. Springs are allowed on board. It is very easy to design weapons based on accumulating potential energy across many springs that can then all simultaneously release them. If I can dream some up easily, so can a criminal. It’s also easy to invent mechanisms for self assembly of projectiles during flight, so parts of a projectile can be separately accelerated.
Banned devices that you could smuggle through detectors are also numerous. High pressure gas reservoirs could easily be made using plastics or resins and could be used for a wide variety of pneumatic projectile weapons and contact or impact based stun weapons. Again, precision release mechanism could be designed for 3D printing at home, but a 3D printer isn’t essential, there are lots of ways of solving the engineering problems.
I don’t see how regulating printers would make us safer. After hundreds of thousands of years, we ought to know by now that if someone is intent on harming someone else, there is a huge variety of ways of doing so, using objects or tools that are essential in everyday life and some that don’t need any tools at all, just trained hands.
Technology comes and goes, but nutters, criminals, terrorists and fanatics are here to stay. Only the innocent suffer the inconvenience of following the rules. It’s surely better to make less vulnerable systems.