What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Screw: A type of fastener consisting of a screw head and a screw rod (a cylinder with an external thread), which needs to be used in conjunction with a nut to fasten and connect two parts with through holes. and widely used in people's lives. In real life, due to the vibration of the machine, the workpiece is loose at the connection between the screw and the nut, and the nut needs to be tightened frequently, which is time-consuming and laborious, delays time, and reduces the production efficiency, so how to reduce the production process. Frequent tightening of screws has become an unsolved problem for people. Therefore, there is an urgent need to provide a slotted screw.
Gaskets are divided into: flat washer - grade C, large washer - grade A and C, extra large washer - grade C, small washer - grade A, flat washer - grade A, flat washer - chamfer type - Grade A, high-strength washers for steel structure, spherical washers, cone washers, square bevel washers for I-beam, square bevel washers for channel steel, standard spring washers, light spring washers, heavy spring washers, internal tooth lock washers , Internal serrated lock washers, external serrated lock washers, external serrated lock washers, single-ear stop washers, double-ear stop washers, outer tongue stop washers and stop washers for round nuts, etc.
When using screws, if you can understand the mechanical properties of screws first, then you can use screws better. Different types of screws have different mechanical properties, and the different mechanical properties lead to different occasions when screws are used. 1. Self-tapping screws: mechanical performance requirements 1. Heart hardness: standard value HRC28-38. When testing, take the section 1-2 times the diameter of the name from the tail. If the length of the name is too short, it can be embedded first, and then the hardness is measured. 2. Surface hardness: standard MIN HV450. 3. Carburized layer: standard 4#-6#: 0.05-0.18mm, 8#-12#: 0.10-0.23 mm, 14#: 0.13-0.28 mm. The main purpose of carburizing is to enhance the surface hardness and ensure the strength of the teeth. If the decarburization is too deep and the carburization is insufficient, the strength of the teeth will not meet the requirements, that is, the teeth will be damaged during the screw-in test. 4. Torque: standard specification 4#5#6#7#8#10#12#14#A tooth 14212835455696145AB tooth 142128354565102165. 5. Screw-in test: screw the self-tapping screw into a steel plate with a reserved test hole. The self-tapping screw should form a matching thread in the test plate, and the thread of the screw itself will not be deformed or damaged until the end. Tapered threads pass completely through the test plate. The screw-in test is only applicable to AB, B, BP and other types of self-tapping screws. It is stipulated in IFI that the test plate shall be prepared from semi-hard low-carbon cold-rolled steel, and the hardness of the steel plate is 70–85HRB in Rockwell. The standard specification of the steel plate, that is, the thickness, is shown in the table below. The test hole should be punched or drilled, and the tolerance is the specified nominal diameter (see the table below) ± 0.025mm. Specifications 6#7#8#10#12#1/4 Test plate thickness (mm) 1.85-1.953.12-3.234.68-4.84 Aperture (mm) ±0.0252.953.263.454.044.765.50.
Guangdong Yueluo Hardware Industry Co., Ltd. relates to a rivet nut fastener, which includes a body, and the rivet part of the body extends into the product to be processed. It is characterized in that trapezoidal teeth are formed on the joint surface of the body and the product to be processed. Or triangular teeth, there is a circular groove below it, and the height of the riveting part is 0.5-1mm smaller than the thickness of the processed product. Guangdong Yueluo Hardware Industry Co., Ltd. is suitable for riveting of any sheet metal materials, such as carbon steel plate, copper plate, aluminum plate, stainless steel plate, aluminum alloy plate, etc. Solid, high riveting surface flatness, providing good electrical contact performance.
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