What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In order to solve the above-mentioned technical problems, a technical scheme adopted by Guangdong Yueluo Hardware Industry Co., Ltd. is: a rivet capable of selecting a breaking point is provided, comprising a nail body and a mandrel, and the mandrel is sequentially provided with from the head to the tail. Hemispherical head, cone and cylinder, the cones are provided with at least three, the mandrel penetrates into the nail body from the bottom of the nail body, and then goes out from the head of the nail body, the hemispherical head and the cylinder Exposed on the bottom of the nail body and the outside of the head, the cones are all arranged inside the nail body.
There are two grades of hexagonal nuts, one is grade 4.8, ordinary nuts, and the other is grade 8 nuts. For more industry knowledge about nuts, you can read the nut specification table and the national standard specification table of the nut industry. Knowledge of these nut specification sheets and industry standards. Allows us to have a deeper understanding of the nut.
Although there are many types of self-tapping screws, they all have the following common points: (1) They are generally made of carburized steel (accounting for 99% of the total output). Also available in stainless steel or non-ferrous metals. (2) The product must be heat treated. Carbon steel self-tapping screws must be carburized, and stainless steel self-tapping screws must be solution hardened. In order to make the self-tapping screw meet the mechanical properties and performance required by the standard. (3) The product has high surface hardness and good core toughness. That is, inner softness and outer rigidity. This is a major feature of the performance requirements of self-tapping screws. If the surface hardness is low, it cannot be screwed into the matrix; if the toughness of the core is poor, it will break as soon as it is screwed, and it cannot be used. Therefore, inner soft outer steel is a very important requirement for self-tapping screws to meet the performance requirements. (4) The surface of the product needs surface protection treatment, generally electroplating treatment. The surface of some products must be treated with phosphate (phosphating), such as wallboard self-tapping screws are mostly phosphated. (5) Produced by cold heading process. It is recommended to use high-speed cold heading machine and high-speed thread rolling machine or high-speed planetary thread rolling machine for production. The emphasis here is on high speed to ensure product quality. Only self-tapping screws produced by high-speed machines have well-formed heads and high-quality threads.
The material of the round head three 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 socket head cap screws, 10B21 wires are often used to make them. 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 manufacturers of round head three combination screws 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. Introduction to the basic knowledge of electroplating round head combination screw electroplating generally refers to the de-plating of iron combination screws. Electroplating is divided into environmental protection and non-environmental protection. Commonly used combination screw electroplating colors include green color zinc, green blue zinc, green white zinc, green nickel, red color, white zinc, white nickel, etc. Cross recessed combination screws, hexagon combination bolts and self-tapping combination screws are used in the same way as the corresponding cross recessed screws, hexagon head bolts and self-tapping screws. The main feature of these combination screws is that they are equipped with corresponding washers, which are very convenient to use.
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