Structural bolts are specifically designed for use with heavy hex nuts in the connection of structural members (as opposed to tapped holes). The nuts for structural connections shall conform to ASTM A563 or ASTM A194. The washers used for structural connections shall meet ASTM F436 specifications. This specification covers both flat circular and beveled washers. The structural Bolts following ASTM F3125/F3125M is a structural bolt specification covering inch and metric bolt grades is to use thicker nuts and shorter thread lengths to obtain the required ductility by plastic deformation of the threads within the nut. The structural bolts manufacturer assembly is used in both preloaded and non-preloaded applications, and it can be argued that in the event of failure by thread plastic deformation the assembly still acts as a non-preloaded assembly. This specification contains 4 inch series bolting grades: A325, F1852, A490, and F2280. These will be addressed in this article. When looking at the mechanical requirements of bolts it appears that a grade A325 and SAE J429 Grade 5 are identical as do the grade A490 and the SAE J429 Grade 8.