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
12 0.515 78 0.875 0.850 1.010 0.969 1132 0.364 0.302
58 0.642 1116 1.062 1.031 1.227 1.175 2764 0.444 0.378
34 0.768 114 1.250 1.212 1.443 1.383 12 0.524 0.455
78 0.895 1716 1.438 1.394 1.660 1.589 3764 0.604 0.531
1 1.022 158 1.625 1.575 1.876 1.796 4364 0.700 0.591
118 1.149 11316 1.812 1.756 2.093 2.002 34 0.780 0.658
114 1.277 2 2.00 1.938 2.309 2.209 2732 0.876 0.749
138 1.404 2316 2.188 2.119 2.526 2.416 2932 0.940 0.810
112 1.531 238 2.375 2.300 2.742 2.622 1 1.036 0.902
158 1.658 2916 2.562 2.481 2.959 2.829 1332 1.116 0.978
134 1.785 234 2.750 2.662 3.175 3.035 1532 1.196 1.054
178 1.912 21516 2.938 2.844 3.392 3.242 114 1.276 1.130
2 2.039 318 3.125 3.025 3.608 3.449 11132 1.388 1.175
214 2.305 312 3.500 3.388 4.041 3.862 112 1.548 1.327
212 2.559 378 3.875 3.750 4.474 4.275 12132 1.708 1.479

Dimensions per ASME B18.2.1 2010