Hex Bolts
Grade A – Intended for Hex Head Bolts and 
studs/threaded rod having a minimum tensile strength of 60 ksi in general applications.
Grade B – Intended for Heavy Hex Head, these bolts, studs/threaded rod having a tensile strength of 60 to 100 ksi and intended for flanged joins in piping systems with cast iron flanges.
Grade C – has been replaced by F1554 Spec for Anchor Bolts, Steel, 36, 55 and 105-ksi Yield
Domestic and Imported
1/2″ up to 4″ Diameter
Standard Thread Length Formulas
Bolt lengths ≤ 6″: Thread length = (2 X diameter) + 1/4″
Bolt lengths > 6″: Thread length = (2 X diameter) + 1/2″
Table 2: Hex Bolt Dimensions
| Bolt Dia | Body Dia | Width Across Flats (F) | Width Across Corners (C) | Height (H) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Max | Min | Basic | Max | Min | Max | Min | Basic | Max | Min | |
| 3/8 | 0.388 | 0.360 | 9/16 | 0.562 | 0.544 | 0.650 | 0.620 | 1/4 | 0.268 | 0.226 |
| 1/2 | 0.515 | 0.482 | 3/4 | 0.750 | 0.725 | 0.866 | 0.826 | 11/32 | 0.364 | 0.302 |
| 5/8 | 0.642 | 0.605 | 15/16 | 0.938 | 0.906 | 1.083 | 1.033 | 27/64 | 0.444 | 0.378 |
| 3/4 | 0.768 | 0.729 | 1-1/8 | 1.125 | 1.088 | 1.299 | 1.240 | 1/2 | 0.524 | 0.455 |
| 7/8 | 0.895 | 0.852 | 1-5/16 | 1.312 | 1.269 | 1.516 | 1.447 | 37/64 | 0.604 | 0.531 |
| 1 | 1.022 | 0.976 | 1-1/2 | 1.500 | 1.450 | 1.732 | 1.653 | 43/64 | 0.700 | 0.591 |
| 1-1/8 | 1.149 | 1.098 | 1-11/16 | 1.688 | 1.631 | 1.949 | 1.859 | 3/4 | 0.780 | 0.658 |
| 1-1/4 | 1.277 | 1.223 | 1-7/8 | 1.875 | 1.812 | 2.165 | 2.066 | 27/32 | 0.876 | 0.749 |
| 1-3/8 | 1.404 | 1.345 | 2-1/16 | 2.062 | 1.994 | 2.382 | 2.273 | 29/32 | 0.940 | 0.810 |
| 1-1/2 | 1.531 | 1.470 | 2-1/4 | 2.250 | 2.175 | 2.598 | 2.480 | 1 | 1.036 | 0.902 |
| 1-3/4 | 1.785 | 1.716 | 2-5/8 | 2.625 | 2.538 | 3.031 | 2.893 | 1-5/32 | 1.196 | 1.054 |
| 2 | 2.039 | 1.964 | 3 | 3.000 | 2.900 | 3.464 | 3.306 | 1-11/32 | 1.388 | 1.175 |
| 2-1/4 | 2.305 | 2.214 | 3-3/8 | 3.375 | 3.262 | 3.897 | 3.719 | 1-1/2 | 1.548 | 1.327 |
| 2-1/2 | 2.559 | 2.461 | 3-3/4 | 3.750 | 3.625 | 4.330 | 4.133 | 1-21/32 | 1.708 | 1.479 |
| Source: ASME B18.2.1 1996 | ||||||||||
Table 10 Hex Head Bolt Length Ranges
| Bolt Diameter | Length up to 1" (incl) | over 1" to 2-1/2 (incl) | 2-1/2" to 4" (incl) | 4" to 6" (incl) | Over 6" |
|---|---|---|---|---|---|
| 1/2" | +0.02 to -0.03 | +0.04 to -0.06 | +0.06 to -0.08 | +0.08 to -0.10 | +0.12 to -0.18 |
| 5/8" | +0.02 to -0.03 | +0.06 to -0.08 | +0.08 to -0.10 | +0.10 to -0.10 | +0.12 to -0.18 |
| 3/4" | +0.02 to -0.03 | +0.06 to -0.08 | +0.08 to -0.10 | +0.10 to -0.10 | +0.14 to -0.18 |
| 7/8" | - | +0.08 to -0.10 | +0.10 to -0.14 | +0.12 to -0.16 | +0.16 to -0.20 |
| 1" | - | +0.08 to -0.10 | +0.10 to -0.14 | +0.12 to -0.16 | +0.16 to -0.20 |
| 1-1/8" | - | +0.12 to -0.12 | +0.16 to -0.16 | +0.18 to -0.18 | +0.22 to -0.22 |
| 1-1/4" | - | +0.12 to -0.12 | +0.16 to -0.16 | +0.18 to -0.18 | +0.22 to -0.22 |
| 1-3/8" | - | +0.12 to -0.12 | +0.16 to -0.16 | +0.18 to -0.18 | +0.22 to -0.22 |
| 1-1/2" | - | +0.12 to -0.12 | +0.16 to -0.16 | +0.18 to -0.18 | +0.22 to -0.22 |
| 1-1/2" & over | - | +0.18 to -0.18 | +0.20 to -0.20 | +0.22 to -0.22 | +0.24 to -0.24 |
| Source: ASME B18.2.1 2003 E-15 | |||||
Other Bolts Available:
- TEE Head Bolts
- Dome Head Bolts
- Stainless Steel
- Brass
- Aluminum
- Special Alloys
