Misuse of fasteners(2)

Update:15 Jun 2019
Summary:

4, a mother multi-pad During the installation process, […]

4, a mother multi-pad
During the installation process, sometimes the bolts after assembly are too long, so some people install a lot of spring washers on one bolt, so that the spring washers will be unevenly biased during the fastening process, which will cause breakage. The pre-tightening force of the bolt is lowered, or an eccentric load is generated, which reduces the reliability of the bolt connection.
5, the gasket is too large
Sometimes, due to the lack of a gasket of a suitable outer diameter, a person replaces it with a gasket having a larger inner diameter. In this way, the contact area of ​​the underside of the bolt with the washer is small, the bearing pressure or the locking force of the washer is lowered, and the bolt is easy to loose under the action of vibration and impact load.
6, the torque does not match
Many people think that the bolts should be “never tight”, so they consciously increase the tightening torque of the bolts. As a result, the bolts are buckled, and there are important bolts for tightening the torque, and there are personnel diagrams to save the adjustable wrench. When screwed, the result is often loose due to insufficient torque, causing mechanical failure.
7, improper lockup
Important bolts should be locked with a lockout after assembly. When using a split pin lock, the common mistake is to lock with a thin open lock or a half-piece open lock; the common mistake with the spring washer is that the washer opening is too small and loses its elasticity; The common mistake is to lock the locking piece at the corner of the nut; the common mistake of locking with a double nut is to install the thinner nut and not tighten it tightly.
Therefore, when using and selecting fasteners, in addition to referencing national standards or industry standards, open-minded consultation and study with professionals and companies can effectively avoid misunderstandings, improve the level of operation, and reduce the impact of fastener loosening and breakage. Even the accident happened.