Who can tell me about the development history of threads and the importance of CNC turning of high-precision threads?

Threads are one of the earliest simple machines invented by humans. In ancient times, people used threads to fix armor on shirts, lift objects, and press oil and wine products. At the end of the 18th century, British engineer Henry Maudslag invented the threaded screw lathe. After the first industrial revolution, the British invented the lathe, die and tap, laying the technical foundation for the mass production of threaded parts. In 1841, the Englishman Joseph Whitworth proposed the world's first national thread standard (BS84, Whitworth thread, B.S.W. and B.S.F.), thus establishing the technical system of thread standards. In 1905, Englishman William Taylor invented the thread gauge design principle (Taylor's principle). Since then, the UK has become the first country in the world to fully master thread processing and testing technology. The British thread standard is the ancestor of the current thread standards in the world. The British thread standard was the first to be recognized and promoted worldwide.

There are three most influential fastening threads in the world. They are: British Whitworth thread, American Saybolt thread, and French metric thread. There are two most influential pipe threads: British Whitworth pipe thread and American Brinell pipe thread. These five most influential threads all came out in the 19th century. They established the technical system for thread standardization. Most other threads adopt or draw lessons from their standard structures.

The National Thread (N) standard of the United States was developed based on the British Whitworth thread. After World War II, it was transformed into the Unified Thread (UN) used by all Allied Powers in World War II. This is the world's first international standard recognized by an international organization. The American pipe thread standard was independently developed by Americans. Together with the British pipe thread, it constitutes the two pillars of the pipe thread standard field in the world today. American-made trapezoidal threads (Acme) and zigzag threads were also recognized by the Allies in World War II.

Therefore, American standard threads have an extremely important impact on modern international trade. Metric plain thread (M) is derived from the American national thread (N), which is widely used in continental Europe and is incorporated into the ISO standard. When the metric unit system (the metric system is the unit of length) was determined as the international legal unit of measurement, the status of metric ordinary threads in international trade was further enhanced. Now, metric ordinary threads can not only compete with American and British threads, but also show the momentum to gradually replace American and British threads. In the future, the United States and the United Kingdom will increase the proportion of adopting metric thread standards, and metric thread standards are the future development direction. However, in actual production and application, the use of the three types of threads must be properly handled according to the characteristics of British, American, and metric threads. Any extreme behavior is incorrect and undesirable.