The site includes files for parts of 3D printers for building and modifying open source 3D printers, as well as sophisticated engine designs for planes and other large feats of engineering, as well as cars, and appliances. GrabCAD is a general 3D file hosting site, catering to not only 3D printing fans, but anyone with an interest in engineering or 3D modeling. Instructables is also great for families looking to build a fun project together while teaching their children about engineering, and assembling something from parts.

This is great for gaining experience and confidence in 3D design and printing, and general engineering and DIY skills. Simply pick a project you find interesting – such as their 3D printed CO2 canister rockets and launchpad – and print and assemble the project in steps as per the designers’ instructions. With a full range of projects, not just for 3D printing but involving electronics and other projects also, Instructables focuses on the educational aspect. Owned by Autodesk, Instructables is a free STL file and general project building site that encourages designers to post step-by-step instructions on how to assemble and build these intriguing projects. Instructables - Free 3D Printer files with great guides You will undoubtedly find dozens of great 3D printer models for you to 3D print on Thingiverse, ranging from video game or TV/film characters, 3D printed miniatures, decorative models, and STL files for holding your pens and stationery. Not only can you download these free 3D printer models, but you are encouraged to post your prints and edits and remixes. The repository how hosts an incredible range of STL files that you can download for free, with no registering necessary. One of the largest free STL file sites in the world, Thingiverse was first set up by 3D printer company Makerbot back in 2008 so users could upload their 3D printer model designs for the world to download and print. Part 1: Sites Hosting Free STL Files Thingiverse - Largest selection of free STL files

– Site for downloading industrial 3D files.

STLFinder – STL file search engine for searching other sites.

Cults – Many free STL files as well as premium 3D printer models.

Part 2: Sites hosting both free and paid-for 3D printer files

The NIH 3D Print Exchange – Free Medical 3D Printer Models.