GB /T 5781 – 2000 – Bu lông lục giác
| Screw Thread | M5 | M6 | M8 | M10 | M12 | (M14) | M16 | (M18) | M20 | (M22) | M24 | (M27) | |
| P | Pitch | 0.8 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | 2.5 | 2.5 | 2.5 | 3 | 3 |
| a | max | 2.4 | 3 | 4 | 4.5 | 5.3 | 6 | 6 | 7.5 | 7.5 | 7.5 | 9 | 9 |
| min | 0.8 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | 2.5 | 2.5 | 2.5 | 3 | 3 | |
| c | max | 0.5 | 0.5 | 0.6 | 0.6 | 0.6 | 0.6 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 |
| da | max | 6 | 7.2 | 10.2 | 12.2 | 14.7 | 16.7 | 18.7 | 21.2 | 24.4 | 26.4 | 28.4 | 32.4 |
| dw | min | 6.74 | 8.74 | 11.47 | 14.47 | 16.47 | 19.15 | 22 | 24.85 | 27.7 | 31.35 | 33.25 | 38 |
| e | min | 8.63 | 10.89 | 14.2 | 17.59 | 19.85 | 22.78 | 26.17 | 29.56 | 32.95 | 37.29 | 39.55 | 45.2 |
| k | Nominal Size | 3.5 | 4 | 5.3 | 6.4 | 7.5 | 8.8 | 10 | 11.5 | 12.5 | 14 | 15 | 17 |
| max | 3.875 | 4.375 | 5.675 | 6.85 | 7.95 | 9.25 | 10.75 | 12.4 | 13.4 | 14.9 | 15.9 | 17.9 | |
| min | 3.125 | 3.625 | 4.925 | 5.95 | 7.05 | 8.35 | 9.25 | 10.6 | 11.6 | 13.1 | 14.1 | 16.1 | |
| k1 | min | 2.19 | 2.54 | 3.45 | 4.17 | 4.94 | 5.85 | 6.48 | 7.42 | 8.12 | 9.17 | 9.87 | 11.27 |
| r | min | 0.2 | 0.25 | 0.4 | 0.4 | 0.6 | 0.6 | 0.6 | 0.6 | 0.8 | 0.8 | 0.8 | 1 |
| s | max=nominal size | 8.00 | 10.00 | 13.00 | 16.00 | 18.00 | 21.00 | 24.00 | 27.00 | 30.00 | 34 | 36 | 41 |
| min | 7.64 | 9.64 | 12.57 | 15.57 | 17.57 | 20.16 | 23.16 | 26.16 | 29.16 | 33 | 35 | 40 | |
| Weight of per 1000 steel products(≈kg) | – | – | – | – | – | – | – | – | – | – | – | – | |
| Screw Thread | M30 | (M33) | M36 | (M39) | M42 | (M45) | M48 | (M52) | M56 | (M60) | M64 | ||
| P | Pitch | 3.5 | 3.5 | 4 | 4 | 4.5 | 4.5 | 5 | 5 | 5.5 | 5.5 | 6 | |
| a | max | 10.5 | 10.5 | 12 | 12 | 13.5 | 13.5 | 15 | 15 | 16.5 | 16.5 | 18 | |
| min | 3.5 | 3.5 | 4 | 4 | 4.5 | 4.5 | 5 | 5 | 5.5 | 5.5 | 6 | ||
| c | max | 0.8 | 0.8 | 0.8 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |
| da | max | 35.4 | 38.4 | 42.4 | 45.4 | 48.6 | 52.6 | 56.6 | 62.6 | 67 | 71 | 75 | |
| dw | min | 42.75 | 46.55 | 51.11 | 55.86 | 59.95 | 64.7 | 69.45 | 74.2 | 78.66 | 83.41 | 88.16 | |
| e | min | 50.85 | 55.37 | 60.79 | 66.44 | 71.3 | 76.95 | 82.6 | 88.25 | 93.56 | 99.21 | 104.86 | |
| k | Nominal Size | 18.7 | 21 | 22.5 | 25 | 26 | 28 | 30 | 33 | 35 | 38 | 40 | |
| max | 19.75 | 22.05 | 23.55 | 26.05 | 27.05 | 29.05 | 31.05 | 34.25 | 36.25 | 39.25 | 41.25 | ||
| min | 17.65 | 19.95 | 21.45 | 23.95 | 24.95 | 26.95 | 28.95 | 31.75 | 33.75 | 36.75 | 38.75 | ||
| k1 | min | 12.36 | 13.97 | 15.02 | 16.77 | 17.47 | 18.87 | 20.27 | 22.23 | 23.63 | 25.73 | 27.13 | |
| r | min | 1 | 1 | 1 | 1 | 1.2 | 1.2 | 1.6 | 1.6 | 2 | 2 | 2 | |
| s | max=nominal size | 46 | 50 | 55.0 | 60.0 | 65.0 | 70.0 | 75.0 | 80.0 | 85.0 | 90.0 | 95.0 | |
| min | 45 | 49 | 53.8 | 58.8 | 63.1 | 68.1 | 73.1 | 78.1 | 82.8 | 87.8 | 92.8 | ||
| Weight of per 1000 steel products(≈kg) | – | – | – | – | – | – | – | – | – | – | – | ||
