Sparrowvsrevolution writes in with a story at Forbes about Makerbot deleting gun component blueprints on Thingiverse. "In the wake of the Newtown, Connecticut shootings, the 3D-printing firm Makerbot has deleted a collection of blueprints for gun components from Thingiverse, its popular user-generated content website that hosts 3D-printable files. Though Thingiverse has long banned designs for weapons and their components in its terms of service, it rarely enforced the rule until the last few days, when the company's lawyer sent notices to users that their software models for gun parts were being purged from the site. Gun control advocates were especially concerned about the appearance of lower receivers for semi-automatic weapons that have appeared on Thingiverse. The lower receiver is the the 'body' of a gun, and its most regulated component. So 3D-printing that piece at home and attaching other parts ordered by mail might allow a lethal weapon to be obtained without any legal barriers or identification. Makerbot's move to delete those files may have been inspired in part by a group calling itself Defense Distributed, which announced its intention to create an entirely 3D-printable gun in August and planned to potentially upload it to Thingiverse. Defense Distributed says it's not deterred by Makerbot's move and will host the plans on its own site."