What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Self-locking nuts generally rely on friction. The principle is to press the embossed teeth into the preset holes of the sheet metal. Generally, the diameter of the square preset holes is slightly smaller than that of the rivet nut. The nut is connected with the locking mechanism. When the nut is tightened, the locking mechanism locks the ruler body, and the ruler frame cannot move freely to achieve the purpose of locking; when the nut is loosened, the locking mechanism disengages the ruler body, and the ruler frame edge body movement
Each self-tapping screw is composed of three parts: the head, the shank and the end of the shank. The composition of each self-tapping screw has four major elements: head shape, wrenching method, thread type, and end form. 1. Head Shapes There are various head shapes. There are round head (semi-round head), flat round head, round head flange (with pad), flat round head flange (with pad), pan head, pan head flange (with pad), countersunk head, semi-countersunk head, Cylinder head, spherical cylinder head, horn head, hexagonal head, hexagonal flange head, hexagonal flange (with pad) head, etc. 2. Wrenching method The wrenching method refers to the way of twisting the head of the screw when installing and tightening the screw. There are two basic methods: external wrench and internal wrench. Generally speaking, external wrenching will allow more torque than any form of internal wrench (internal groove). External wrench: hexagon, hexagonal flange surface, hexagonal flange, hexagonal flower shape, etc.; internal wrench: flat groove, cross groove H type, cross groove Z type, cross groove F type, square groove, compound groove, inner flower Key, inner hexagon flower, inner triangle, inner hexagon, inner 12 corner, clutch slot, six-blade slot, high torque cross slot, etc. 3. There are many types of threads, including self-tapping threads (wide thread), machine threads (ordinary threads), drywall screw threads, fiberboard screw threads, and some other special threads. In addition, threads can be divided into single-lead (single-end), double-lead (double-end), multi-lead (multiple-end) and high-low thread double-end threads. 4. Terminal form There are two main types of terminal form: tapered end and flat end. However, according to the needs of use, at the screw-in part of the end, grooves, grooves, incisions or parts with a similar drill shape can be processed with cutting function. In some standards, it is also a tapered end or a flat end, and there are different forms such as a rounded end.
The side gear thrust washer used in the automobile differential is a flat washer, which is installed between the differential housing and the side gear to prevent the side gear from retreating. Due to the high-speed rotation of the side gear when the differential is working, it is necessary to ensure that the contact surfaces on both sides of the flat gasket are well lubricated.
Cross recessed pan head screws refer to cross recessed machine wire screws, which are represented by the letters PM. The country stipulates that the thread specification is M1.6-M10, the performance level is 4.8, A-50, A2-70, CU2, CU3 and AL4, H-type and Z-type cross recessed, and the product grade is Class A cross recessed pan head screws . If other technical requirements are needed, they should be selected from the current standards (such as GB/T196, GB/T3106, GB/T3098.1, GB/T3098.6 and GB/T3098.10).
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