What identification markings does a SAE Grade 5 bolt have?

A SAE Grade 5 bolt is characterized by having three radial lines marked on its head. These markings serve as a quick visual identification to indicate the grade and strength of the bolt. In the context of fasteners, marking systems like this are crucial for ensuring that the correct components are used in applications where specific strength characteristics are required. The presence of three radial lines distinguishes Grade 5 bolts from other grades, allowing machinists and engineers to quickly ascertain their suitability for various assembly needs. This system enhances safety and reliability in construction and manufacturing, where the wrong grade of bolt could lead to equipment failure or structural issues.