Inventory of misunderstandings in using fasteners

Fasteners are a kind of fastener connection parts commonly used in people's daily life, ranging from small screws on watches to large mechanical parts or airport bolts and nuts. The application standard of fasteners is very common, but in the process of our application, will you encounter some misunderstandings, for example, if you don’t have fine-thread bolts, can you use coarse-thread bolts instead? For these problems, Changzhou Wujin Dajia Standard Parts Co., Ltd. reminds us that it is impossible. According to the summary, when using fasteners, the common misunderstandings mainly include the following categories. We look forward to helping you. Misunderstanding 1 of using fasteners: use coarse threads instead of fine threads There are many key joints on the equipment, such as rotating shafts, etc. Most of the bolts are fine thread external threads. If there are missing parts during maintenance, some maintenance personnel will replace them with coarse thread bolts, which should also be avoided. Due to the large inner diameter of fine thread bolts, small pitch and angle, high strength, good locking performance, and strong ability to bear impact, vibration and interchangeable loads. Once it is replaced by coarse tooth bolts, it is easy to fall off or fall off, break off, and even cause mechanical accidents. Misunderstanding 2 of using fasteners: The holes are not suitable for the bolts that bear the lateral load and shear stress on the equipment, such as the rotating shaft bolts, water pump flywheel bolts, and their matching with the bolt holes is a clearance fit. The installation should be firm and reliable, and can be used Take side force. Some people do not pay attention to inspection during the installation process, and they still continue to install when there is a large gap between the bolt and the bolt hole, which is very easy to cause bolt loosening or disconnection accidents. Misunderstanding 3 of using fasteners: Thickened nuts increase connection reliability Some people incorrectly think that thickened nuts can increase the number of working cycles of external threads and improve the reliability of connections. But in fact, the thicker the nut, the more uneven the load distribution between the threads of each circle, and the easier it is for the joint to loosen. Misunderstanding 4 of using fasteners: After the successful assembly of one female and multiple pads, sometimes the bolts are too long, so many people install self-locking nuts on the bolts. In this case, the self-locking nut will break due to uneven bearing force during the fastening process, which will reduce the pre-tightening force of the bolt, and may also cause axial load, reducing the reliability of the bolt connection. Misunderstanding 5 of using fasteners: The tighter the better, many workers have such a misunderstanding: that is, they think that the bolts should be "tighter than soft", so they deliberately increase the tightening torque, resulting in loosening of the bolts. In addition, there are some key bolts that need to be tightened with torque, but some people use an adjustable wrench to tighten them for convenience. As a result, the torque is not enough, causing the bolts to loosen, and even cause equipment failure.