What happens if a bucking bar is too light during riveting?

When a bucking bar is too light during the riveting process, it fails to provide the necessary weight and inertia needed to properly upset the rivet. A bucking bar's primary function is to apply sufficient force against the rivet while the rivet gun impacts the opposite side. If the bar is inadequately heavy, the rivet won't be compressed effectively, resulting in a poor-quality joint. Properly upset rivets create a tight connection by deforming the rivet's head against the material being joined, ensuring structural integrity. Without adequate upsetting, the rivet may not fully engage or may pull through the material, compromising the assembly's strength and reliability. Thus, proper bucking bar weight is essential to achieve the desired rivet formation for a secure and durable bond.