Engineer's Edge is a great reference for a wide variety of engineering, design, and manufacturing information. Most of the material is in the form of online calculators and equation charts, which save users time that would otherwise be spent flipping through books. Other resources such as part specifications (e.g., drill sizes, gauge charts) and material properties are also available. Interactive conversion tools, beam statics analyzers, and calculators for many different applications are free and very easy to use. An active discussion forum allows industry workers to communicate and share ideas. No registration is required.