Hexagon Flange Bolt ( https://www.chinaweigao.com/product/bolt/hexagon-socket-head-bolt.html ) is a kind of mechanical parts that are used for fastening and connection and are extremely widely used. All kinds of fasteners can be seen on various machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, meters and supplies. It is characterized by a wide variety of specifications, different performance and uses, and a high degree of standardization, serialization, and generalization. Therefore, some people call a type of fasteners that have national standards as standard fasteners, or simply standard parts. Fasteners are the most widely used mechanical basic parts.
1. Use coarse teeth instead of fine teeth
There are many important connecting parts on the machine, such as the drive shaft, and most of the bolts are fine thread. If there are missing parts during maintenance, some maintenance personnel will use coarse bolts instead, which should be avoided.
Because the inner diameter of the fine pitch bolt is larger, the pitch and outer angle are smaller, the strength is high, the self-locking performance is good, and the ability to withstand impact, vibration and exchange loads is relatively strong. Once replaced with coarse-threaded bolts, it is prone to loosening or detachment, disassembly, and even mechanical accidents.
2. The pores are not matched
The bolts on the machine that bear the lateral load and shear force, such as the drive shaft bolts and flywheel bolts, are matched with the bolt holes as transitional fits. The assembly should be strong and reliable, and can withstand lateral forces. Someone does not pay attention to the inspection during the assembly process, and continues to install when there is a large gap between the bolt and the bolt hole, which is prone to bolt loose or cut off accidents.
3. Thicken nuts increase connection reliability
Some people mistakenly believe that thickening the nut can increase the number of working turns of the thread and improve the reliability of the coupling. But in fact, the thicker the nut, the more uneven the load distribution between the threads of each circle, and the easier the coupling is to loosen.
4. One female with multiple pads
After the installation is complete, sometimes the bolt is too long, so someone installs an additional spring washer on the bolt. In this case, the spring washer will break due to uneven force during the strengthening process, which will cause the bolt to be pre-tensioned. If the tightening force is decreased, eccentric load may be generated, which reduces the reliability of bolt connection.
5. The washer is too large
Sometimes there is a lack of washers of the right size, and some workers will replace them with washers with larger inner diameters. In this case, the contact area under the bolt head with the washers is small, which will reduce the bearing pressure or locking force of the washers. If the working environment is There are vibrations and shocks, and the bolts are easy to loosen.
6. The false solidity of Threaded Rods And Eye Bolts ( https://www.chinaweigao.com/product/bolt/eye-bolt.html )

If the bolts, nuts, or threads are rusted, or impurities such as scale, iron filings, etc., must be cleaned before assembly; burrs, sand and other impurities on the joint surface of the coupling must also be removed. Otherwise, when the bolts are tightened, they appear to be tightened on the surface, but in fact the couplings are not really tightened. Under such false solidity, the bolt will loosen quickly if vibration, load shock and temperature change occur.