Bucking is the process of providing solid backing to a rivet using a heavy, shaped metal tool. As the pneumatic rivet gun hammers the factory head on one side, the inertia of the bucking bar on the blind side crushes the rivet tail into a flattened field head. This action tightly clamps the two pieces of base metal together.
Heard on the job
I need someone to buck these rivets inside the wing spar while I run the gun.