When driving a rivet, which tool is essential to apply pressure against the rivet shank?

When driving a rivet, using a bucking bar is essential because it applies necessary pressure against the rivet shank from the back side of the workpiece. This pressure ensures that the rivet is properly formed and securely fastened to the material. The bucking bar is typically heavy and shaped to fit the specific area of work, allowing the mechanic to effectively shape the tail of the rivet as it is compressed by the rivet gun.

The action of the bucking bar complements the rivet gun, which provides the force needed to drive the rivet. Together, they ensure that the rivet sets correctly and achieves the necessary strength for the joint being created. The bucking bar's role is fundamental in preventing the deformation of the materials being joined and ensuring that the rivet heads are formed evenly and without excessive damage to the surrounding material.