Of all the wonderful things a 3D printer can make, a model car for aerodynamic testing, a replacement tea mug for camping or even a linker for connecting the very different connectors of Lego and Brio toy trains (other toys are available), it was perhaps inevitable that someone would upload the data set to allow owners of these rapid prototyping machines to "print" a gun, with all the ethical implications of such a design.


I remember first hearing about 3D printing back in the late 1980s. How it would revolutionize prototyping, manufacturing and ultimately allow consumers to download designs to make products in their homes. It is in the last couple of years that 3D printers are entering the mainstream although they're not quite as ubiquitous as conventional 2D printers for text on paper or other materials. The concept of 3D printing represents a shift away from mass-manufacturing, allowing distributed manufacturing to be carried out at point of use. Wikipedia tells us that 3D printers are used in "jewelry, footwear, industrial design, architecture, engineering and construction (AEC), automotive, aerospace, dental and medical industries, education, geographic information systems, civil engineering, and many other fields."


And, now, as I say, guns.


According to news reports at the beginning of May (http://www.guardian.co.uk/world/2013/may/06/3-handgun-fired-cody-wilson), law student Cody Wilson, 25, successfully tested plastic handgun built by his Texas firm Defense Distributed using an $8,000 (about £5000) 3D printer. It took a year of development to come up with the data set to control the printer and allow it to produce a working gun from 15 or so components and a metal firing pain of the kind available from any hardware store. Wilson is apparently planning to upload the "digital blueprints" online so that anyone with the equipment could make their own gun. Of course, this demonstration and plans has caused widespread outcry and panic while gun advocates see it as a sea change in ownership that will improve their right to bear arms.


In the firing tests first widely reported in the media, the gun is held in a metal clamp and a string used to squeeze the trigger to fire the .038 caliber bullet. Later demonstrations showed Wilson firing the gun manually, according to the BBC (http://www.bbc.co.uk/news/science-environment-22421185). However, one has to wonder just how safe a plastic gun would be on repeated use. Digits2Widgets’ Design Director Jonathan Rowley is concerned that plastic components will not necessarily withstand ballistic pressures (http://digits2widgets.wordpress.com/2013/05/08/3d-printed-gun-public-safety-warning/). That said, I am sure that there will be individuals or companies finding ways to optimize the process and to work around construction issues to very reliable successors.


So, are we likely to see a rise in the number of gun-toting 3D printer users? I suspect not, it isn't as if it's difficult to get hold of a gun in some parts of the world. We have to assume that despite the recurrence of drive-by killings, mass shootings and other lethal activity and the media frenzy that seems to accompany each, that the vast majority of people across the world do not want to own a lethal weapon, manufactured, printed or otherwise because they prefer not to live their lives with the facile ability to kill another human being in an instant. Thankfully.


The data for the printable 3D gun were put online to much anxiety from the authorities and the US State Department urged Defense Distributed to take them down. However, as is the way of the Internet once any digital item is online it will most likely never disappear and notorious file-sharing site, The Pirate Bay, now has a copy that is being distributed to anyone who cares to download it.


The Pirate Bay says it will not remove the files from its system. Indeed, the organization simply hosts links to so-called Bit Torrent files which allow peer-to-peer distributions of any files among users. More than 100,000 downloads were clocked up within 48 hours, according to a report on Friday 10th May from Torrent Freak (http://torrentfreak.com/pirate-bay-takes-over-distribution-of-censored-3d-printable-gun-130510/)

 David Bradley blogs at http://www.sciencebase.com and tweets @sciencebase, he is author of the popular science book "Deceived Wisdom".