What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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 technical process of nickel-phosphorus plating for high-strength bolts consists of three parts: The first part is the pre-treatment process, including the precision and appearance inspection of high-strength bolts before plating, manual degreasing, immersion degreasing, pickling, electro-activation and flash nickel plating and other processes; the second part is the electroless nickel plating treatment process; the third part is the post-treatment process, including the processes of hydrogen-displacing heat treatment, polishing and finished product inspection. As follows: Bolt chemical composition inspection → bolt pre-plating accuracy, visual inspection → manual degreasing → visual inspection → immersion degreasing → hot water washing → cold water washing → pickling → cold water washing → electric activation → cold water washing → flash nickel plating → cold water washing → Deionized water washing → Electroless nickel plating → Deionized water washing → Cold water washing → Hydrogen removal → Polishing → Finished product inspection.
Yueluo is about a special fastener and its screwdriver. That is, the Y screw and its screwdriver. In order to prevent the leakage of new product manufacturing technology and prohibit others from arbitrarily opening the shell of the new product or disassembling the relevant parts, it is necessary to take effective precautions against their own products, and the use of special fasteners is one of the purposes of Yueluo. This kind of screw can also be widely used in the fixation of some public equipment, for the fastening and fixing of parts that are afraid of disassembly and theft, so as to play a certain protective role.
A: Metric Screws B: US Screws C: Inch Screws A: Metric Machine Screws: Metric Ex: M3 x 6 – PPB : M3 Machine Screws, 6mm Length, Cross, Flat Head, Black Plated. Finish Code: Finishing Specifications Head Code: The shape of the head. The shape of the screw head. Cylindrical head. Half head. sinking head. Spherical cylinder head. Pan head. Half round head. Hex Head.
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