Bolt and nut - 2.1mm thread pitch, 12.09 TPI

thingiverse

Bolt and Nut Print Test Results The diameter of the bolt before threading is 14 millimeters, while the internal diameter of the nut measures 12.4, 12.5, or 12.6 millimeters. A thread per inch ratio of 12.09 results in a thread pitch of 2.1 millimeters. Printing at a layer thickness of 0.2 millimeters provides sufficient resolution to produce a functional bolt and nut set. In my case, the idle nut diameter is 12.5 millimeters, with 12.4 being too tight and 12.6 slightly loose. By scaling both the bolt and nut diameters while maintaining a constant thread per inch ratio and thread pitch of 2.1 millimeters, as well as a 1.5-millimeter difference between the two diameters, optimal results can be achieved.