Fastener is a kind of fastener connection parts commonly used in people's daily life, ranging from small screws on watches to large and medium-sized mechanical parts or airport bolt nut connection. The application standard of fasteners is very common, but in the whole process of application, do you encounter some mistakes, for example, if we don't have fine thread bolts, can we still replace coarse thread bolts? Changzhou Wujin Dajia Standard Parts Co., Ltd. reminded us that it is impossible for us to solve this problem. According to the summary, there are several common misconceptions in the application of fasteners. We look forward to providing some assistance to you.


Misunderstanding of using fasteners 1: replace fine teeth with coarse teeth


There are many key connectors on the equipment, such as rotating shafts, and most of the bolts are fine external threads. In case of missing parts during maintenance, some maintenance personnel will replace them with coarse thread bolts, which should also be prevented. As the inner diameter of fine thread bolt is relatively large, the pitch and diagonal angle are small, the compression strength is high, the locking characteristics are good, and the working capacity of bearing impact, vibration and exchange load is also strong. Once the coarse thread bolt is replaced, it is very easy to fall off or fall off, and even cause mechanical equipment safety accidents.


Misunderstanding of fastener use 2: pore mismatch


The bolts on the equipment that bear the effect of transverse load and shear stress, such as rotating shaft bolts and water pump flywheel bolts, are matched with the bolt holes for clearance, and should be installed firmly and reliably, and can bear the side force. Some people do not pay attention to the inspection during the whole installation process. When there is a large gap between the bolt and the bolt hole, they still install again, which is very easy to cause a safety accident of bolt loosening or disconnection.


Misunderstanding of using fasteners 3: Thickened nuts increase connection reliability


Some people incorrectly believe that thickened nuts can increase the number of working cycles of external threads and improve the reliability of connectors. However, in fact, the thicker the nut is, the more uneven the load distribution among the external threads of each circle is, and the connector is more easily loosened.


Misunderstanding of using fasteners 4: One female with multiple gaskets


After successful assembly, sometimes the bolt is too long, so many people attach self-locking nuts to the bolt. In this case, the uneven bearing force of the self-locking nut will break during the whole process of fastening, which will reduce the pre tightening force of the bolt, and may also cause axial load, reducing the reliability of the bolt connection.


Misunderstandings in using fasteners 5: The tighter the screw, the better


Many workers have the misconception that bolts should be "tightened rather than soft", so they deliberately increase the tightening torque, resulting in loose bolts. In addition, there are some key bolts that need to be tightened with torque, but some people use a spanner wrench to tighten them because of the convenience of the drawing. As a result, the torque is not enough, resulting in bolt looseness, and even equipment failure.