What material is a bucking bar primarily made of?

A bucking bar is primarily made from hardened steel due to its need for strength, durability, and resistance to wear during the riveting process. The function of a bucking bar is to provide a backing surface against which a rivet can be driven, ensuring that the rivet is properly set without deforming the bar itself. Hardened steel has a high hardness level, making it ideal for handling the stresses involved in riveting operations while minimizing deformation or damage to the tool. The weight of hardened steel also aids in efficiently bucking the rivet, promoting a firm application of pressure. Materials like aluminum, plastic, and wood do not deliver the necessary mechanical properties to withstand the intense forces experienced during riveting, which is why they are less suited for making bucking bars.