free stl, where to find them?
In this page we report a list of sites from which it is possible to download free stl files ready to be printed in 3d both free and paid.
Thingiverse
Thingiverse is a community created by Makerbot, one of the largest manufacturers of 3D printers. Born with the rapid spread of 3d printers, it has become one of the largest 3D design communities in the world, allowing you to share and download over a million files for free.
grabcad
GrabCad belongs to Stratasys, America’s leading professional 3D printer manufacturer. Made up of a community of mechanical engineers, it contains everything, over 1,000,000 free files ranging from various genres, from mechanics to household items to costume jewelery.