BOLTS-Open-Library-for-standard-parts-screws-nuts-washers-...-

When you use a CAD software to create a design, this design consists usually of two different types of components: Custom parts that are specific to your purposes and have to be custom made (e.g. by 3D printing), and standard parts like nuts and bolts that you can buy in a hardware store. A standard parts library relieves you from the tedious task of modeling standard parts by providing them readily usable, so that you can focus on the interesting aspects of your design.