How They’re Determined by the SAE, and How They’re Identified by Markings on the Fastener Head Automotive bolted joints operate under demanding cyclic loads, high temperatures, and increasingly lightweight designs. As a result, understanding bolt grades – and the standards behind them-is essential for fastener engineers working in OEM, Tier
bolt grades
Understanding Nut and Bolt Grades: Why the Nut Should Be Weaker Than the Bolt
When it comes to mechanical fastening, engineers often focus on bolt strength—after all, it’s doing the heavy lifting, right? But there’s more to the story. In a bolted joint, the relationship between bolt grade and nut grade plays a critical role in the strength, safety, and serviceability of the assembly.


