What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Screw (pinyin: luógǎn, English: screw): a cylinder with a spiral groove cut on the outer surface or a cone cut with a tapered spiral groove. The screw has a different head, the head is called an external hexagon screw. There are others, such as large flat screws, socket head screws and so on.
The national standard name of the cross recessed small pan head three combination screw is the cross recessed small pan head screw, the spring washer and the flat washer assembly. The national label is GB/T9074.8-1988. This 1988 refers to the year, that is, this standard is the standard issued by the country in 1988. The specifications of the cross recessed small pan head three combination screws, the company's minimum is M2.5, the shortest is 5mm, the largest is M10, and the longest is 90mm.
Hexagon nuts are divided into three types: I type, II type and thin type according to the nominal thickness. Nuts above grade 8 are divided into two types: type 1 and type II. Type I hexagon nuts are the most widely used. Type 1 nuts are divided into three grades: A, B, and C. Among them, grade A and grade B nuts are suitable for machines, equipment and structures with small surface roughness and high precision requirements. Class C nuts are used on machines, equipment or structures with rough surfaces and low precision requirements.
Stainless steel screws do not necessarily corrode and rust, but that stainless steel screws have a stronger ability to withstand corrosion and rust than iron screws. But stainless steel screws can still rust under certain circumstances. So under what conditions are stainless steel screws prone to rust! What is the cause of rust? Stainless steel screws have better characteristics, strong corrosion resistance, high temperature resistance, and strong rust resistance. But it will rust in harsh environments. For example, stainless steel screws are exposed to the sun and the wind every day under very humid conditions. Over time, it will definitely rust a little. For example, in contact with some acid-base chemicals to cause chemical reactions. cause corrosion and rust. There are also bad stainless steel screws, such as stainless steel SUS201 screws used in seawater. Due to long-term immersion, SUS201 stainless steel screws themselves are not suitable for use in salty seawater. cause corrosion and rust. For the use of marine products, it is generally recommended to use stainless steel SUS316 screws, because 316 stainless steel screws have better performance such as corrosion resistance. From the above, it can be concluded that stainless steel screws will still corrode and rust under certain circumstances. Therefore, this requires the rational use of stainless steel screws. Use stainless steel screws of different materials in different situations. And in different occasions, when using stainless steel screws, special attention is also required, and some details need to be considered more. Try to control the corrosion and rust of stainless steel screws as much as possible.
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