What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
NPT, PT, G are all pipe threads. NPT is the abbreviation of National (American) Pipe Thread, which belongs to the American standard 60-degree taper pipe thread, which is used in North America. National standards can be found in GB/T12716-1991 PT is the abbreviation of Pipe Thread, which is a 55-degree sealed conical pipe thread, which belongs to the Whitworth thread family and is mostly used in Europe and the Commonwealth of Nations. Commonly used in water and gas pipe industry, the taper is specified as 1:16. The national standard can be found in GB/T7306-2000 G is a 55 degree non-threaded sealing pipe thread, which belongs to the Whitworth thread family. Marked as G stands for cylindrical thread. National standards can be found in GB/T7307-2001 In addition, the 1/4, 1/2, 1/8 marks in the thread refer to the diameter of the pipe, and the unit is inches. People in the industry usually refer to thread size in points, 1 inch equals 8 points, 1/4 inch is 2 points, and so on. G seems to be the general name for pipe threads (Guan), and the division of 55 and 60 degrees is functional, commonly known as pipe circle. That is, the thread is machined from a cylindrical surface. ZG is commonly known as pipe cone, that is, the thread is made of a conical surface. The general water pipe joints are like this. Rc means conical internal thread ZG means taper pipe thread, 3/4 means inch mark, which is 3/4 inch conical pipe Thread, there is in the Hardware Manual. The national standard stipulates that the major diameter of ZG 3/4 thread is 26.44 mm. Please refer to Metric, American and British Thread Standard Manual (Third Edition). Its representation method should be: ZG 3 /4″. Among them (〃) is the representative symbol for inches. One inch is equal to 8 inches. The origin of 3/4 is 6/8=3/4. Commonly known as 6 points. Similarly, the major diameter of ZG 1/2″ thread≈21 mm. Commonly known as 4 points. ZG 1″ thread diameter ≈ 33 mm. Commonly known as 1 inch. ZG 1 1/2″ thread pipe outer diameter ≈ 48 mm. Commonly known as 1 inch and a half. Taper pipe thread is very similar to pipe thread, the difference is Only in the taper. Note that the basic size of the pipe thread and ordinary thread is different. DN is the nominal diameter
The retaining ring is a ring-shaped component fastened on the shaft and the inner hole. Its main function is to prevent other components installed on the shaft and the inner hole from sliding axially on the shaft. It is a fixed standard part.
The traditional fixture shown in Figure 2 is composed of a hardened support cylinder and a hardened shear bar, and has a simple structure. The cylindrical pin is loaded into the hardened support cylinder, and the shear test is completed by applying an axial load to the hardened shear bar. Since the standard stipulates that the gap between the loading part and the supporting part does not exceed 0.15mm, in order to ensure the matching of the gap during the shear test of the cylindrical pin, the diameter of the cylindrical pin on the cylinder is generally equal to the theoretical cylindrical pin. In practical application, the cylindrical pin is irregular in size after heat treatment. To realize the shear test, the cylindrical pin must be inserted into the hole with the help of external force, which is difficult to install and clamp and takes a long time. If the double-sided shearing is performed, that is If the cylindrical pins need to be installed on both sides, the time is doubled, and the notch of the cylindrical pins cannot be guaranteed to face upwards.
In order to meet the requirements of anti-loosening bolts of parts with small surface hardness such as plastic parts, Yueluo provides a spring washer and the installation structure of the spring washer, which can effectively reduce the damage of the spring washer to the surface of the parts. And meet the anti-loosening effect of the spring washer. The technical solution provided by Yueluo is a spring washer, which includes a washer body with at least two raised claws on the washer body
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