shearbolt

A shear bolt is a type of fastener designed to break or "shear" at a predetermined load. This deliberate failure mechanism is used to protect equipment or structures from damage caused by overloads or impacts. When the force applied exceeds the bolt's shear strength, the bolt fractures, effectively disconnecting the two components it was joining. This prevents more expensive or critical parts from being damaged.

Shear bolts are commonly found in machinery where sudden stalls or impacts are a possibility. Examples include agricultural equipment like tillers and balers, snow blowers, and certain types of power transmission systems such as PTO shafts. In these applications, the shear bolt acts as a sacrificial element, absorbing the shock of an overload and breaking, thus saving the main drive components.

The shear strength of a bolt is determined by its material properties, diameter, and the length of the shear plane. Manufacturers specify the torque or load at which a particular shear bolt will fail. Replacing a sheared bolt is typically a straightforward repair, allowing the equipment to be quickly put back into operation. It is important to use the correct replacement shear bolt as specified by the equipment manufacturer to ensure proper protection. Using a bolt with a higher shear strength may defeat the protective purpose, while one with lower strength might shear too easily during normal operation.