What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The assembly of hollow rivets and flat head screws riveted on the cover plate is assembled in the product. Compared with the method of connecting with bolts, the loading and unloading speed can improve the efficiency by about 80% to 90%, and is widely used. The assembly needs to riveted hollow rivets and flat head screws on the cover plate, and ensure that the riveted flat head screws can rotate flexibly. When riveting, it is necessary to use special tools to riveted the hollow rivets, flat head screws and cover plates together for riveting. In the existing riveting process, the oval head screw is often damaged due to the action of external force. The positioning process is cumbersome and the work efficiency is low.
With the continuous strengthening of infrastructure construction, the continuous increase of construction scale and the complexity of construction, the particularity of the requirements for construction equipment, materials, tools and equipment is also getting higher and higher, such as buildings, power stations, railway tunnels The channel steel used in these special construction environments requires the use of a special bolt, which must be easy to put in, easy to use
4. Manufacturing and assembly Due to the limitations of manufacturing technology and accuracy, there are sharp corners on the edge of the thread or the dimensional coordination between parts is not coordinated. During the initial assembly, the screw-in and screw-out torque may fluctuate or fluctuate to a certain extent. After a certain number of running-in, more accurate reusability characteristics of the lock nut can be obtained.
The self-tapping locking screw is composed of three parts: the head, the stem and the end of the stem from beginning to end. The composition of each self-tapping screw has four major elements: head shape, wrenching method, thread type, and end type. Head Shapes - Head shapes come in all shapes and sizes. There are round head (semi-round head), oblate head, round head flange (with pad), oblate 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 gasket), etc. Wrench Styles - There are various ways of wrenching. External wrench: hexagonal, hexagonal flange, hexagonal flange, hexagonal flower shape, etc.; internal wrench: slotted, cross groove H type (Phillips), cross groove Z type (Pozidriv), cross groove F type (Frearson) , Square groove (Scrulox), compound groove, internal spline, internal hexagon flower (plum groove), internal triangle, internal hexagon, internal 12-angle, clutch groove, six-blade groove, high torque cross groove and so on. Thread Types - There are many types of threads. There are self-tapping threads (wide thread), machine threads, drywall screw threads, fiberboard screw threads, and some other special threads. In addition, the thread can be divided into single lead (single head), double lead (double head), multi-lead (multiple head) and high and low thread double head thread. End type - The end type mainly includes saw end and flat end. However, according to the function of use, grooves, grooves, incisions or parts with a cutting function can be processed. In some standards, the same saw end or flat end, there are different forms. There are various changes in the head shape, wrenching method, thread type and shank end type of self-tapping screws. They can be combined with each other to show many different products belonging to the category of self-tapping screws.
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