ASTM 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. | |||
|---|---|---|---|---|
| 1⁄2 | 5⁄8 | 3⁄4 thru 1 | 11⁄8 thru 11⁄2 | |
| 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.
| 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 | |
| 1⁄2 | 0.515 | 7⁄8 | 0.875 | 0.850 | 1.010 | 0.969 | 5⁄16 | 0.323 | 0.302 | 1.00 |
| 5⁄8 | 0.642 | 11⁄16 | 1.062 | 1.031 | 1.227 | 1.175 | 25⁄64 | 0.403 | 0.378 | 1.25 |
| 3⁄4 | 0.768 | 11⁄4 | 1.250 | 1.212 | 1.443 | 1.383 | 15⁄32 | 0.483 | 0.455 | 1.38 |
| 7⁄8 | 0.895 | 17⁄16 | 1.438 | 1.394 | 1.660 | 1.589 | 35⁄64 | 0.563 | 0.531 | 1.50 |
| 1 | 1.022 | 15⁄8 | 1.625 | 1.575 | 1.876 | 1.796 | 39⁄64 | 0.627 | 0.591 | 1.75 |
| 11⁄8 | 1.149 | 113⁄16 | 1.812 | 1.756 | 2.093 | 2.002 | 11⁄16 | 0.718 | 0.658 | 2.00 |
| 11⁄4 | 1.277 | 2 | 2.00 | 1.938 | 2.309 | 2.209 | 25⁄32 | 0.813 | 0.749 | 2.00 |
| 13⁄8 | 1.404 | 23⁄16 | 2.188 | 2.119 | 2.526 | 2.416 | 27⁄32 | 0.878 | 0.810 | 2.25 |
| 11⁄2 | 1.531 | 23⁄8 | 2.375 | 2.300 | 2.742 | 2.622 | 15⁄16 | 0.974 | 0.902 | 2.25 |
|
Dimensions per ASME B18.2.6 2011 |
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