What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The technical solution adopted by Guangdong Yueluo Hardware Industry Co., Ltd. to solve the problems of the prior art is: a patch nut, which is characterized in that it includes a nut body, and the nut body has a welding end face, and the edge of the welding end face forms a The serrated teeth protruding outwards of the ring.
One of the steps in the screw production and processing process is to slot the screw head to facilitate the use of a screwdriver when tightening or loosening the screw. Generally, companies use manual sorting, and then use the cutting knife to slot the front end screws through the track, which is inefficient, and because the screws are not fixed, the cutting knife may easily fly out or break the blade during cutting. It is a safety problem, and after cutting, the screw head has rough workmanship and burrs, which is easy to hurt the hand.
Material and process requirements The self-tapping locking screw should be made of high-quality carburized steel cold heading, generally no larger than M12. The finished material should be drawn with a high total reduction rate before cold heading, so that the cold heading must be spheroidized. Annealing, in order to enhance the surface hardness and the toughness of the core, most of them are made of medium and low carbon steel. The chemical composition of the material in the standard is only for guidance. The C content is 0.13%~0.37%, the Mn content is 0.64%~1.71%, and the B content can reach 0.005%. The elements of S, P, Mn and Si in the commonly used steel are generally lower than those of the ordinary bolt steel of the same grade. And the surface quality of the material is strictly controlled to reduce deformation resistance and prevent deformation and cracking. Commonly used grades are 20Mn, 15MnB, SWRCH22A, 1022A and medium carbon steel, medium carbon alloy steel SWRCH35K, SCM435, SCR435, etc. Self-tapping locking screws are threads with an arc-shaped triangular cross-section, so the formulation of cold heading and wire rolling processes, as well as the design and manufacture of cold heading dies and special rolling plates are very important. Self-tapping locking screws require a high-hard surface for cutting and extruding capabilities due to the need for self-tapping low carbon steel. At the same time, there must be sufficient core strength and toughness to prevent twisting and breaking during work. The heat treatment process of this type of screw belongs to shallow carburizing. Regardless of whether it is made of low carbon steel or medium carbon or medium carbon alloy steel, its core hardness must be guaranteed to be within the range of 28~38HRC (9.8 grade) 33~39HRC (10.9 grade) and not less than the minimum tensile load of 930MPa (9.8 grade), 1040MPa (grade 10.9), depending on the material, the minimum tempering temperature is 420℃. In order to ensure that the self-tapping locking screw can be smoothly screwed into the prefabricated cylindrical hole, the end of the screw should be hardened by high-frequency quenching to ensure that at least one to three thread teeth are hardened, and the minimum surface hardness is 45HRC.
The existing adjusting screw is generally composed of a screw and a nut on the top of the screw. The screw is driven to rotate by means of a screwdriver, and then the screw is driven to rotate. In and out, adjusting other objects connected to it and changing position accordingly.
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