In the connection between shafts and hubs of equipment such as motors and reducers, 12.9-grade black zinc hexagon socket flat point knurled set screws play a crucial role. The flat point design allows them to fit tightly against the cylindrical surface of the shaft, generating concentrated gripping force to ensure the synchronous rotation of the hub and shaft, effectively preventing relative displacement and guaranteeing stable power transmission. For example, in the lead screw transmission system of machine tools, these screws can accurately fix the lead screw and coupling, ensuring the machining precision of the machine tool.
Compact space is a common feature in the assembly of electronic equipment. This type of set screw, with no protruding head, can perfectly fit into limited spaces. In processes such as fixing the heat dissipation module and installing the hard disk of laptops, it can firmly secure components. Moreover, the hexagon socket design facilitates operation with small tools, improving assembly efficiency. At the same time, the black zinc coating enhances the screw’s corrosion resistance, adapting to the complex internal working environment of electronic equipment.
Medical devices have extremely high requirements for the precision and stability of components. In surgical instruments and medical testing equipment, 12.9-grade black zinc hexagon socket flat point knurled set screws are used to fix key parts, ensuring the reliability and safety of the instruments during use. Their high strength can withstand frequent operational stress, and the knurled design increases friction to prevent the screws from loosening in vibrating environments, thus ensuring the accurate operation of medical devices.
The assembly of core automotive components such as engines and transmissions cannot do without this type of set screw. In aspects like fixing the camshaft of the engine and positioning the gear shaft of the transmission, it can provide reliable fastening force and adapt to the high-temperature, high-pressure, and vibrating environment during vehicle operation. In automotive maintenance, these screws are easy to disassemble and replace, improving maintenance efficiency.
The metric thread specification usually ranges from M2 to M16. Smaller specifications such as M2 and M3 are often used in scenarios with strict space requirements and low stress, such as electronic equipment; larger specifications such as M8, M10, and M12 are suitable for fields bearing large loads, such as mechanical transmission and automotive manufacturing. For instance, in mechanical transmission systems, M10-sized screws can meet the strength requirements for general shaft-hub connections.
The length of the screw generally ranges from 6mm to 100mm. Appropriate lengths should be selected for different application scenarios. In electronic equipment, short screws of 6mm or 8mm may be sufficient; while in the fixing of multi-layer components in large mechanical equipment, longer screws of 50mm or even 100mm may be required. For example, when fixing internal components of large machine tool casings, longer screws can penetrate multi-layer structures to achieve stable connection.
The 12.9 grade represents the high-strength characteristic of this set screw. Its material is usually SCM435 alloy steel or 35CrMo material. After heat treatment, the surface hardness can reach 39-44 HRC, enabling it to withstand large tensile and shear forces, and is suitable for occasions with high requirements for mechanical performance.
The black zinc coating not only gives the screw a unique appearance but, more importantly, enhances its corrosion resistance. In harsh environments such as humidity, acid, and alkali, the black zinc coating can effectively protect the screw matrix and extend its service life. For example, in fields such as outdoor mechanical equipment and shipbuilding, this corrosion resistance feature is particularly important.
12.9-grade black zinc hexagon socket flat point knurled set screws (DIN916K) have become indispensable key components in the industrial field due to their diverse application scenarios and rich specification options. In practical applications, selecting screws of appropriate specifications accurately according to specific needs can give full play to their performance advantages and ensure the stable operation and reliable work of equipment.
