What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The material of the combination screw is divided into iron and stainless steel. The iron ones are made of different iron screw wires. Generally, the wire of the combination screw is 1010, 1018, 10B21 and so on. 10B21 is used to make 8.8 grade combination screws. Like 8.8 grade hexagon socket head combination screws, 10B21 wire is often used. When done, go to heat treatment. After heat treatment, remove hydrogen and electroplating. This is to prevent the spring washer of the socket head cap screw from breaking. Stainless steel combination screws, in the combination screw market, generally refer to stainless steel SUS304 combination screws. 201 combination screws generally do very little. Few combination screw manufacturers produce 201 combination screws. Because the hardness of the screw wire of stainless steel 201 is not well controlled, it is easy to produce cracks.
Guangdong Yueluo Hardware Industry Co., Ltd. discloses a rivetless rivet, which includes a nail body and a mandrel, wherein one end of the nail body is provided with a nail body brim, and the nail body brim is provided with a nail body. A coaxial counterbore, the nail body is provided with a through hole coaxial with the nail body, the counterbore is communicated with the through hole and its diameter is larger than the diameter of the through hole, and one end of the mandrel is provided with a mandrel cap The other end is provided with a clamp head, and the end is provided with an elastic groove for retracting the clamp head inward or opening it outward. The clamping head on the core is clamped on the boss formed by the countersunk hole and the through hole. The above-mentioned rivet-free rivet is not only simple, compact and reasonable in structure; riveting is simple and does not require professional tools and equipment; and it is easy to disassemble after riveting, can be reused, has a wide range of applications, and is reliable and stable in connection.
Further, the pressure riveting portion and the pressure-bearing portion are both columnar structures, the outer diameter of the pressure-bearing portion is larger than the outer diameter of the pressure riveting portion, the pressure riveting portion is a stepped structure, and the diameter of the lower end of the pressure riveting portion is smaller than that of the pressure riveting portion. The diameter of the upper end of the rivet part.
Generally, the countersunk head is used in places where the surface is required to be smooth without protrusions, because the countersunk head can be screwed into the part. Round heads can also be screwed into parts. The tightening force of the square head can be larger, but the size is large. In addition, in order to meet the needs of locking after installation, there are holes in the head and holes in the rod. These holes can prevent the bolts from loosening when they are vibrated. Some bolts without threads should be made thin, called thin-waisted bolts. This kind of bolt is beneficial to the connection under variable force. There are special high-strength bolts on the steel structure, the head will be larger, and the size will also change. In addition, there are special uses: for T-slot bolts, which are most used on machine tool fixtures, with special shapes, and both sides of the head should be cut off. Anchor bolts, used for machine and ground connection and fixing, come in many shapes. U-bolts, as previously described. and many more. There are also special studs for welding. One end has a thread and the other end is not. It can be welded to the part, and the other side can directly screw the nut.
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