When removing the rivet shank, what tool is used adjacent to the rivet to support the structure and prevent deformation?

The bucking bar is the appropriate tool used adjacent to the rivet when removing the rivet shank, as it provides necessary support to the structure. When working with rivets, especially during the removal process, it's critical to maintain the integrity of the surrounding material. The bucking bar helps to distribute the impact forces, preventing undesirable deformation or damage to the adjacent structure. This is particularly important in aerospace applications, where the integrity and strength of structural components are vital for safety and performance.

While other tools like a hammer, punch, or rivet gun play various roles in riveting tasks, they do not fulfill the specific support function needed during rivet removal. The hammer is primarily used for driving rivets, a punch is meant for making or enlarging holes, and a rivet gun is used for setting rivets rather than support during their removal. Therefore, the bucking bar is essential for safeguarding the surrounding area while effectively removing rivets.