the same imperial fractions. The Unified thread angle is 60° and has flattened crests (Whitworth crests are rounded). Thread pitch is the same in both systems except that the thread pitch for the 1/2 in. (inch) bolt is 12 threads per inch (tpi) in BSW versus 13 tpi in the UNC.

The first modern International Organization (Intergovernmental Organization), the International Telegraph Union (now the International Telecommunication Union),