What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The middle pins on upright and horizontal pianos are also called balance pins. The middle pins are installed on the middle sleepers of the keyboard frame and play the role of fixing the keys. Generally, there are 88 keys in the piano. The pins are matched with the pin holes, and the keys are installed on each middle pin one by one through the pin holes. Due to the large number of middle pins and keys, in the production and installation process, in order to ensure the flatness of the 88 keys after installation, it is necessary to debug the middle pins and keys one by one, or add paper circles to the middle fixed part on the middle pins. The flatness of the 88 keys is kept the same. This debugging method is extremely cumbersome and increases the workload of debugging. Moreover, when adding paper circles, the keys need to be disassembled frequently. Due to the limitation of the installation space of the keys, it is troublesome to disassemble the keys, and it is easy to install and disassemble the keys many times. Damage to the pin holes on the keys, degrading the quality of the piano.
④ Screw tooth type A: Self-tapping sharp tail (Japanese standard type 1) sparse AB: Self-tapping sharp tail (Japanese standard type 4) dense; B: Self-tapping flat tail (Japanese standard type 2) sparse; C: Self-tapping Tapping flat tail (the third type of Japanese standard) dense; P: double wire teeth Type triangle teeth CCT: C type triangle teeth PTT: P type triangle teeth STT: S type triangle teeth
In the riveting connection of various structural parts, waterproof lantern rivets have been widely used in riveting environments that require waterproofing. After the riveting parts are riveted, the waterproof structure area of the mandrel and the waterproof structure of the rivet body There is no complete close fit between the areas. In some riveting ranges, the waterproof performance of the rivet is affected. The main reason is that the traditional processing technology of the mandrel and the materials used bring many troubles to the riveting process. is a problem to be solved at present.
As a standard part, it should have its own general specifications. For hexagonal nuts, the commonly used standards are: GB52, GB6170, GB6172 and DIN934. The main differences between them are: GB6170 is thicker than GB52, GB6172 and DIN934. Thick from DIN934, commonly known as thick nut. The other is the difference between the opposite sides, the opposite sides of DIN934, GB6170 and GB6172 in the M8 nut series are 13MM smaller than the opposite side 14MM of GB52, and the opposite sides of M10 nuts, DIN934 and GB52 are 17MM. The opposite side of GB6170 and GB6172 should be 1MM larger, M12 nut, DIN934, GB52's opposite side is 19MM larger than GB6170 and GB6172's opposite side 18MM is 1MM larger. For M14 nuts, the opposite side of DIN934 and GB52 is 22MM, which is 1MM larger than the opposite side of GB6170 and GB6172, which is 21MM. The other is the M22 nut. The opposite side of DIN934 and GB52 is 32MM, which is 2MM smaller than the opposite side of GB6170 and GB6172, which is 34MM. (Besides the thickness of GB6170 and GB6172 are the same, the width of the opposite side is exactly the same) The rest of the specifications can be used in general without considering the thickness.
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