Several ASTM specifications require a hex head that is larger than a standard (finished) hex head. These specifications include: A193, A320 and A307B. Although A325 and A490 bolts also require a heavy hex head, please refer to Structural Bolts for dimensional specifications, since these bolts have shorter thread lengths than standard heavy hex bolts.

Applications

Heavy hex bolts can be used for many different applications that include fastening wood, steel, and other construction materials for projects such as docks, bridges, highway structures, and buildings. Heavy hex bolts with forged heads are also commonly used as headed anchor bolts.

Manufacturing

Portland Bolt manufactures heavy hex bolts from 1/2″ diameter through 2-1/2″ diameter in most ASTM, AASHTO, and SAE specifications. Special tooling can be created to produce nonstandard head dimensions or bolt heads with your company’s name and/or logo.

Stock

Portland Bolt stocks A325 Heavy Hex Structural Bolts.

Standard Thread Lengths

Bolt lengths  6″: Thread length = (2 X diameter) + 1/4″
Bolt lengths > 6″: Thread length = (2 X diameter) + 1/2″

Heavy Hex Dimensions

Click table to show drawingheavy-hex
Bolt Diameter D F C H
Body Diameter Width Across Flats Width Across Corners Height
Max Basic Max Min Max Min Basic Max Min
1/2 0.515 7/8 0.875 0.850 1.010 0.969 11/32 0.364 0.302
5/8 0.642 1-1/16 1.062 1.031 1.227 1.175 27/64 0.444 0.378
3/4 0.768 1-1/4 1.250 1.212 1.443 1.383 1/2 0.524 0.455
7/8 0.895 1-7/16 1.438 1.394 1.660 1.589 37/64 0.604 0.531
1 1.022 1-5/8 1.625 1.575 1.876 1.796 43/64 0.700 0.591
1-1/8 1.149 1-13/16 1.812 1.756 2.093 2.002 3/4 0.780 0.658
1-1/4 1.277 2 2.00 1.938 2.309 2.209 27/32 0.876 0.749
1-3/8 1.404 2-3/16 2.188 2.119 2.526 2.416 29/32 0.940 0.810
1-1/2 1.531 2-3/8 2.375 2.300 2.742 2.622 1 1.036 0.902
1-3/4 1.785 2-3/4 2.750 2.662 3.175 3.035 1-5/32 1.196 1.054
2 2.039 3-1/8 3.125 3.025 3.608 3.449 1-11/32 1.388 1.175
2-1/4 2.305 3-1/2 3.500 3.388 4.041 3.862 1-1/2 1.548 1.327
2-1/2 2.559 3-7/8 3.875 3.750 4.474 4.275 1-21/32 1.708 1.479

Dimensions per ASME B18.2.1 1996