Why Do We Need Standards?
In the early days of the industrial revolution everything was bespoke. The pace of change was limited and the lack of tolerances meant everything had to be hand-fettled. One of the first items in engineering to be standardized was the screw thread.
In a museum near where I live there is a gun made by the Turks in 1464 to bombard the walls of Constantinople. The breech screws on to the barrel had a perfect screw thread. It took until 1841 for Whitworth to propose standard thread forms. A cheaper thread form was standardized in the United States by William Sellers in 1864 (NF, NC). The NC form was compatible with Whitworth in most sizes if you were not too fussy.
In 1948 Britain started to adopt ...