Portland Bolt is often asked which grade should be used in a structural application. More specifically, when asked what grade is required for a particular fastener that we are receiving an inquiry on, companies will often reply “it’s a structural grade” or “it’s for a structural application”. This usually is the result of a fastener being specified on a drawing, but not having an ASTM grade referenced. Unfortunately this is a little too ambiguous to know what the exact grade of bolt required is. There are two ASTM graded fasteners that are specifically structural bolts, ASTM A325 and ASTM A490. Both of these fasteners typically have a heavy hex head and are used in structural steel connections. The ASTM F3125 specification, which now governs ASTM A325, A325M, A490, A490M, F1852 and F2280, may also be specified, but it is necessary to find out which of the above grades they need under the F3125 specification. If the bolt in question is not being used in this application, then simply calling out a “structural grade” is not enough information to know which grade of fasteners would work best. In this case, the next step would be to contact the engineer involved in the particular project requiring the fasteners and have them specify the appropriate grade.