UNITED STATES STANDARD SIZES OF BOLTS.
| DIAM- ETER. | Distance Across Flats, Square and Hex. | Distance Across Corners, Hex. | Thickness of Head. | ||||
|---|---|---|---|---|---|---|---|
| 1⁄4″ | 1⁄2″ | 9⁄16″ | 1⁄4″ | ||||
| 3⁄8 | 11⁄16 | 25⁄32 | 11⁄32 | ||||
| 1⁄2 | 7⁄8 | 1 | 7⁄16 | ||||
| 5⁄8 | 1 | 1⁄16 | 1 | 7⁄32 | 17⁄32 | ||
| 3⁄4 | 1 | 1⁄4 | 1 | 7⁄16 | 5⁄8 | ||
| 7⁄8 | 1 | 7⁄16 | 1 | 21⁄32 | 21⁄32 | ||
| 1 | 1 | 5⁄8 | 1 | 7⁄8 | 13⁄16 | ||
| 1 | 1⁄8 | 1 | 13⁄16 | 2 | 3⁄32 | 29⁄32 | |
| 1 | 1⁄4 | 2 | 2 | 5⁄16 | 1 | ||
| 1 | 3⁄8 | 2 | 3⁄16 | 2 | 1⁄2 | 1 | 3⁄32 |
| 1 | 1⁄2 | 2 | 3⁄8 | 2 | 3⁄4 | 1 | 3⁄16 |
| 1 | 5⁄8 | 2 | 9⁄16 | 2 | 15⁄16 | 1 | 9⁄32 |
| 1 | 3⁄4 | 2 | 3⁄4 | 3 | 3⁄16 | 1 | 3⁄8 |
| 1 | 7⁄8 | 2 | 15⁄16 | 3 | 13⁄32 | 1 | 15⁄32 |
| 2 | 3 | 1⁄8 | 3 | 5⁄8 | 1 | 9⁄16 | |
| 2 | 1⁄4 | 3 | 1⁄2 | 4 | 1⁄16 | 1 | 3⁄4 |
| 2 | 1⁄2 | 3 | 7⁄8 | 4 | 1⁄2 | 1 | 15⁄16 |
| 2 | 3⁄4 | 4 | 1⁄4 | 4 | 7⁄8 | 2 | 1⁄8 |
| 3 | 4 | 5⁄8 | 5 | 11⁄32 | 2 | 5⁄16 | |