When should pliers be used on bolts and nut heads?

Pliers should never be used on bolts and nut heads because they can easily slip and damage the surfaces of the fasteners. This can lead to rounding off the corners of the nuts or bolts, making them difficult or impossible to remove or tighten effectively. The improper use of pliers can also compromise the integrity of the joint, leading to potential failures in applications where secure fastening is crucial.

Instead, proper tools specifically designed for use with nuts and bolts, such as wrenches or socket sets, should always be utilized. These tools provide the necessary grip and leverage to apply the correct amount of torque without causing damage. Using the right tools not only ensures safety but also maintains the reliability of the assemblies involved in pipefitting tasks.