Fasteners are general names, also called fasteners or s […]
Fasteners are general names, also called fasteners or standard parts. Those with external threads can be called "screws". Screws include screws, bolts and studs. Screws use the physical and mathematical principles of the circular rotation and frictional forces of the bevel of the object to fasten the components and parts of the device step by step. Screws are an indispensable industrial necessity in everyday life: very small screws used in cameras, glasses, wall clocks, electronics, etc .; ordinary screws for televisions, electrical products, musical instruments, furniture, etc .; as for engineering, architecture, bridges, etc. Large screws and nuts; transportation equipment, airplanes, trams, cars, etc. are combined with large and small screws. Screws have important tasks in industry. As long as there is industry on the earth, the function of screws is always important. The screw was created together in the days of production for thousands of years. According to the field of application, it is the first creation of mankind.
Screw (screw), the front part is pointed like a nail, basically it is used in places with pre-made threads; metric threads are in MM (millimeters) as the unit, and its cusp angle is 60 degrees. Both American and British threads are in inches. The tip angle of American threads is also 60 degrees, while the tip angle of British threads is 55 degrees. Because the unit of measurement is different, the method of indicating the various threads is different. For example, M16-2X60 shows a metric thread. His detailed meaning is that the nominal diameter of the screw is 16MM, the pitch is 2MM, and the length is 60MM. Another example: 1 / 4-20X3 / 4 indicates that the screw is an English thread. His detailed meaning is the nominal name of the screw. The diameter 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 screws, you usually add UNC and UNF to the back of the inch screws to distinguish between American coarse teeth and American fine teeth.
Bolts are flat-cylinder-type, that is, they are used in cooperation with nuts. Usually, wrenches are used for things. A type of fastener consisting of a head and a screw (a cylinder with an external thread), which needs to cooperate with a nut to fasten two parts with through holes. This connection method is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is attributed to the detachable connection.