Screws and nuts are indispensable in daily life and industrial production and manufacturing. Screws and nuts are also known as industrial meters. It can be seen that screws and nuts are widely used. The application scope of screws and nuts are: electronic products, mechanical products, digital products, electric equipment. For example, the precision screws used in digital products, DVD, camera, glasses, clocks, electronics and so on. TV, electrical products, Musical Instruments, furniture, etc.