Standard Specification for Screws

The most commonly used standards are the following:
GB-China National Standard (National Standard)
ANSI-American National Standard (American Standard)
DIN-German National Standard (German Standard)
ASME-American Society of Mechanical Engineers Standard
JIS-Japanese National Standard (Japanese Standard)
BSW-British National Standard

In addition to some basic dimension, such as the head thickness and the head opposite side, the most different part of the mentioned standards for screws is the thread.The threads of GB, DIN, JIS, etc. are all in MM (millimeters), collectively referred to as metric threads. Threads like ANSI, ASME, are in inches and are called American standard threads. Besides metric threads and American threads, there is also a BSW-British standard, and the threads are also in inches, commonly known as Whitworth threads.

The metric thread is in MM (mm), and its cusp angle is 60 degrees. Both American and Imperial threads are measured in inches. The cusp angle of the American thread is also 60 degrees, while the cusp angle of the British thread is 55 degrees. Due to the different units of measurement, the representation methods of various threads are also different. For example, M16-2X60 represents a metric thread. It specifically means that the nominal diameter of the screw is 16MM, the pitch is 2MM, and the length is 60MM. Another example: 1/4-20X3/4 means the British system thread. its specific meaning is the nominal diameter of the screw is 1/4 inch (one inch=25.4MM), there are 20 teeth on one inch, and the length is 3/4 inch. In addition, if you want to indicate American-made screws, UNC and UNF are usually added after the British-made screws to distinguish between American-made coarse threads and American-made fine threads.

Yihe enterprise is a company specializing in producing US-made amchine screws ANSI, BS machine screw, bolt corrugated, indlcuidng 2BA, 3BA, 4BA; German-made machine screws DIN (DIN84/ DIN963/ DIN7985/ DIN966/ DIN964/ DIN967); GB Series and other types of standard and non-standard products such as machine screws and all kinds of brass machine screws.