Bolts are indispensable in daily life and industrial production. Bolts are also called the industrial rice. It can be seen that the bolts are widely used. The application range of bolts are: electronic products, mechanical products, digital products, electrical equipment, electromechanical products. Bolts are also useful in ships, vehicles, water conservancy projects, and even chemical experiments. Anyway, bolts are used in many places. Such as precision bolts used on digital products. Miniature bolts used in DVDs, cameras, glasses, watches, electronics, etc.; general bolts for televisions, electrical products, musical instruments, furniture, etc.; as for engineering, construction, and bridges, large bolts and nuts are used; transportation equipment, airplanes, trams, and automobiles And so on, are used for both large and small bolts. Bolts have important tasks in industry. As long as industry exists on the earth, the function of bolts will always be important.