How many screw threads per inch does a Standard National Coarse 1/2 bolt have?

For a Standard National Coarse (UNC) 1/2 bolt, the correct number of threads per inch is indeed 13. This specification is part of the Unified Thread Standard (UTS), which defines threading systems for bolts and screws. The designation "1/2" refers to the nominal diameter of the bolt, while the threads per inch (TPI) are standardized according to the diameter.

In this case, a 1/2-inch bolt falls under a category of fasteners that have been commonly used, where the UNC gives a coarse thread that is more suitable for applications requiring quick assembly and adequate strength. As per the standard tables for UNC threads, a 1/2-inch bolt has a coarse thread TPI of 13.

Understanding this standard is essential for ensuring compatibility in mechanical assembly, as using the wrong thread count can lead to improper fitting and structural failures. Thus, recognizing that 13 threads per inch is the established standard for a 1/2 inch UNC bolt is critical for any practical application involving these fasteners.