1. Use coarse teeth instead of fine teeth

 

There are many important connecting parts on the machine, such as drive shafts, etc., and most of the bolts are fine threads. If there are missing parts during maintenance, some maintenance personnel will use coarse thread bolts instead, which should be avoided. Because the inner diameter of the fine thread 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 shock, vibration and exchange load is relatively strong. Once coarse-threaded bolts are used instead, it is easy to loosen or fall off, break off, and even cause mechanical accidents.

 

Second, the pores do not match

 

The bolts on the machine that are subjected to lateral loads and shear forces, such as drive shaft bolts and flywheel bolts, are transitionally fitted with the bolt holes, and the assembly should be solid and reliable, and can withstand lateral forces. Some people do not pay attention to inspection during the assembly process, and continue to install when there is a large gap between the bolt and the bolt hole, which is prone to bolt loosening or cutting accidents.

 

3. Thickened 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 joint. 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.

 

4. One female with multiple pads

 

After the installation is completed, sometimes the bolts are too long, so some people install additional spring washers on the bolts. In this case, the spring washers will break when the force is uneven during the firming process, so that the bolts are pre-installed. If the tightening force decreases, eccentric load may also occur, which will reduce the reliability of bolted connection.