Hardware
Recommended Nuts and Washers
The recommended grade of nut for an ASTM A325 structural bolt is ASTM A563 Grade D, DH, or C. ASTM A194 2H is also an acceptable substitute. These ASTM grades are all high strength and go through a heat treating process required to develop their mechanical characteristics. The reasoning behind one grade being preferred over another normally has to do with availability. There are certain sizes that may be harder to find in the market place in a given grade, needing to be specially fabricated, in which case a grade substitution would be desired. There may also be situations where the project must follow guidelines requiring that the hardware be melted and manufactured in certain geographical areas. Being that A325 type 3 bolts are made from weathering steel, the grade of nut used would be ASTM A563 Grade DH3 or C3. As far as the washers are concerned, the recommended grade is the ASTM F436 hardened washer, type 1 or 3 depending on the type of bolt grade.
A325 Recommended Hardware
| Nuts | Washers | |||
|---|---|---|---|---|
| Type 1 | Type 3 | Type 1 | Type 3 | |
| Plain | Galvanized | Plain | ||
| A563C, C3, D, DH, DH3 | A563DH | A563C3, DH3 | F436-1 | F436-3 |
| Note: Nuts conforming to A194 Grade 2H are a suitable substitute for use with A325 heavy hex structural bolts. The ASTM A563 Nut Compatibility Chart has a complete list of specifications. | ||||
Heavy Hex Nut Dimensions
| Bolt Diam. | F | C | H | Weight (lbs.) |
|||||
|---|---|---|---|---|---|---|---|---|---|
| Width Across Flats | Width Across Corners | Thickness | |||||||
| Basic | Max | Min | Max | Min | Basic | Max | Min | ||
| 1⁄2 | 7⁄8 | 0.875 | 0.850 | 1.010 | 0.969 | 31⁄64 | 0.504 | 0.464 | 0.07 |
| 5⁄8 | 11⁄16 | 1.062 | 1.031 | 1.227 | 1.175 | 39⁄64 | 0.631 | 0.587 | 0.12 |
| 3⁄4 | 11⁄4 | 1.250 | 1.212 | 1.443 | 1.382 | 47⁄64 | 0.758 | 0.710 | 0.20 |
| 7⁄8 | 17⁄16 | 1.438 | 1.394 | 1.660 | 1.589 | 55⁄64 | 0.885 | 0.833 | 0.30 |
| 1 | 15⁄8 | 1.625 | 1.575 | 1.876 | 1.796 | 63⁄64 | 1.012 | 0.956 | 0.43 |
| 11⁄8 | 113⁄16 | 1.812 | 1.756 | 2.093 | 2.002 | 17⁄64 | 1.139 | 1.079 | 0.59 |
| 11⁄4 | 2 | 2.000 | 1.938 | 2.309 | 2.209 | 17⁄32 | 1.251 | 1.187 | 0.79 |
| 13⁄8 | 23⁄16 | 2.188 | 2.119 | 2.526 | 2.416 | 111⁄32 | 1.378 | 1.310 | 1.02 |
| 11⁄2 | 23⁄8 | 2.375 | 2.300 | 2.742 | 2.622 | 115⁄32 | 1.505 | 1.433 | 1.31 |
Hardened Washer Dimensions
| Bolt Size | B | A | C | Weight (lbs.) Per 1000 Pieces | Part Numbers | ||
|---|---|---|---|---|---|---|---|
| Outside Diameter | Inside Diameter | Thickness | Domestic | ||||
| Min | Max | Black | Galvanized | ||||
| 1⁄2 | 11⁄16 | 17⁄32 | 0.097 | 0.177 | 18 | 16440 | 16441 |
| 5⁄8 | 15⁄16 | 11⁄16 | 0.122 | 0.177 | 33 | 16442 | 16443 |
| 3⁄4 | 115⁄32 | 13⁄16 | 0.122 | 0.177 | 41 | 16444 | 16445 |
| 7⁄8 | 13⁄4 | 15⁄16 | 0.136 | 0.177 | 64 | 16446 | 16447 |
| 1 | 2 | 11⁄16 | 0.136 | 0.177 | 82 | 16448 | 16449 |
| 11⁄8 | 21⁄4 | 13⁄16 | 0.136 | 0.177 | 105 | 16450 | 16451 |
| 11⁄4 | 21⁄2 | 13⁄8 | 0.136 | 0.177 | 133 | 16452 | 16453 |
| 13⁄8 | 23⁄4 | 11⁄2 | 0.136 | 0.177 | 163 | 16454 | 16455 |
| 11⁄2 | 3 | 15⁄8 | 0.136 | 0.177 | 200 | 16456 | 16457 |
Load Indicating Washers (DTI)
Load indicating washers (LIW) or direct tension indicating washers (DTI) are used to develop the correct tension when installing ASTM A325 structural bolts. Standard DTIs and Squirter™ DTIs are manufactured to ASTM F959. They are available as domestically manufactured in the USA and in either plain finish steel or mechanically galvanized. The sizes that they are available coincide with the A325 specification, 1/2″ diameter through 1-1/2″.
Load Indicating Washer Dimensions
| Bolt Size | B | C | A | Number of Protrusions | PTD* Max | Part Numbers | |||
|---|---|---|---|---|---|---|---|---|---|
| Max OD | Thickness After Compression | ID Max | Squirter | Standard | |||||
| Black | Galvanized | Black | Galvanized | ||||||
| 1⁄2 | 1.187 | 0.120 | 0.527 | 4 | 0.788 | 12621 | 12622 | 16485 | 17287 |
| 5⁄8 | 1.375 | 0.140 | 0.658 | 4 | 0.956 | 12623 | 12624 | 15909 | 17288 |
| 3⁄4 | 1.625 | 0.140 | 0.790 | 5 | 1.125 | 12625 | 12626 | 12678 | 17289 |
| 7⁄8 | 1.875 | 0.160 | 0.921 | 5 | 1.294 | 12627 | 12628 | 12645 | 17290 |
| 1 | 2.000 | 0.180 | 1.052 | 6 | 1.463 | 12629 | 12630 | 12646 | 17291 |
| 11⁄8 | 2.250 | 0.180 | 1.183 | 6 | 1.631 | - | - | 18996 | 18997 |
| 11⁄4 | 2.500 | 0.180 | 1.315 | 7 | 1.800 | - | - | 18371 | 17293 |
| 13⁄8 | 2.750 | 0.180 | 1.446 | 7 | 1.969 | - | - | 17294 | 19419 |
| 11⁄2 | 3.000 | 0.180 | 1.577 | 8 | 2.138 | 18408 | - | - | 19418 |