Dimensions

structuralASTM A325 structural bolts are designed for steel to steel connections. Because they are used in such a specific application, they have dimensional characteristics that are unique and limited compared to most other fastener grades. This includes stock sizes available in the market place, length tolerances, short thread lengths, and the actual head dimensions are the same as any heavy hex head bolt (Dimensions per ASME B18.2.6 2011).

Available Sizes

Although technically any size A325 can be custom manufactured, there are certain restrictions as well as common lengths which are more readily available in the marketplace. Depending on the diameter, there may be longer lengths available.

Diameters Allowed: 1/2″ – 1-1/2″
Available Lengths: Up to 6″ – 10″ maximum (depending on diameter)
Available  Finish: Plain Finish or Hot Dip Galvanized
Origin: Import or Domestic

Bolt Length Tolerances

Nominal Length, in. Nominal Size, in.
12 58 34 thru 1 118 thru 112
Thru 6 in. -0.12 -0.12 -0.19 -0.25
Over 6 in. -0.19 -0.25 -0.25 -0.25

Structural Bolt Dimensions

Although the head dimensions for structural bolts are the same as any heavy hex headed fastener per ASME B18.2.6 2011, A325 heavy hex bolts have a shorter thread length than most other construction fastener grades.

Click table to show drawing
Bolt Diameter D F C H T
Body Diameter Width Across Flats Width Across Corners Height Thread Length
Max Basic Max Min Max Min Basic Max Min Basic
12 0.515 78 0.875 0.850 1.010 0.969 516 0.323 0.302 1.00
58 0.642 1116 1.062 1.031 1.227 1.175 2564 0.403 0.378 1.25
34 0.768 114 1.250 1.212 1.443 1.383 1532 0.483 0.455 1.38
78 0.895 1716 1.438 1.394 1.660 1.589 3564 0.563 0.531 1.50
1 1.022 158 1.625 1.575 1.876 1.796 3964 0.627 0.591 1.75
118 1.149 11316 1.812 1.756 2.093 2.002 1116 0.718 0.658 2.00
114 1.277 2 2.00 1.938 2.309 2.209 2532 0.813 0.749 2.00
138 1.404 2316 2.188 2.119 2.526 2.416 2732 0.878 0.810 2.25
112 1.531 238 2.375 2.300 2.742 2.622 1516 0.974 0.902 2.25

Dimensions per ASME B18.2.6 2011