The ASTM A307 is an ASTM International standard for carbon steel bolts and studs ranging from 1/4 inches through 4 inches in diameter which is set by the standards organization ASTM International. Given here is the bolt torque chart for the ASTM A307 bolts. These bolts are categorized into three grades, grade A (Headed bolts), grade B (Headed, Heavy hex bolts) and grade C (Nonheaded anchor bolts) where ASTM A307 Grades A and B has one inch diameter bolt.
| Bolt Size | TPI | Proof | Clamp | |||
|---|---|---|---|---|---|---|
| Tightening Torque (ft lbs) | ||||||
| Galv+Waxed | Galv | Plain | ||||
| 1⁄4 | 20 | 1,145 | 859 | 2 | 4 | 4 |
| 5⁄16 | 18 | 1,886 | 1,415 | 4 | 9 | 7 |
| 3⁄8 | 16 | 2,790 | 2,093 | 7 | 16 | 13 |
| 7⁄16 | 14 | 3,827 | 2,870 | 10 | 26 | 21 |
| 1⁄2 | 13 | 5,108 | 3,831 | 16 | 40 | 32 |
| 9⁄16 | 12 | 6,552 | 4,914 | 23 | 58 | 46 |
| 5⁄8 | 11 | 8,136 | 6,102 | 32 | 79 | 64 |
| 3⁄4 | 10 | 12,024 | 9,018 | 56 | 141 | 113 |
| 7⁄8 | 9 | 15,200 | 11,400 | 83 | 208 | 166 |
| 1 | 8 | 20,000 | 15,000 | 125 | 313 | 250 |
| 11⁄8 | 7 | 25,200 | 18,900 | 177 | 443 | 354 |
| 11⁄4 | 7 | 32,000 | 24,000 | 250 | 625 | 500 |
| 13⁄8 | 6 | 38,100 | 28,575 | 327 | 819 | 655 |
| 11⁄2 | 6 | 46,400 | 34,800 | 435 | 1,088 | 870 |
| 13⁄4 | 5 | 68,400 | 51,300 | 748 | 1,870 | 1,496 |
| 2 | 41⁄2 | 90,000 | 67,500 | 1,125 | 2,813 | 2,250 |
| 21⁄4 | 41⁄2 | 117,000 | 87,750 | 1,645 | 4,113 | 3,291 |
| 21⁄2 | 4 | 144,000 | 108,000 | 2,250 | 5,625 | 4,500 |
| 23⁄4 | 4 | 177,480 | 133,110 | 3,050 | 7,626 | 6,101 |
| 3 | 4 | 214,920 | 161,190 | 4,030 | 10,074 | 8,060 |
| 31⁄4 | 4 | 255,600 | 191,700 | 5,192 | 12,980 | 10,384 |
| 31⁄2 | 4 | 299,880 | 224,910 | 6,560 | 16,400 | 13,120 |
| 33⁄4 | 4 | 347,760 | 260,820 | 8,151 | 20,377 | 16,301 |
| 4 | 4 | 398,880 | 299,160 | 9,972 | 24,930 | 19,944 |
The ASTM A307 Bolt Torque Table provides tension, torque and TPI against their corresponding sizes. In heavy timber construction, A307 bolts are used for wood and it has a minimum tensile strength of 60 ksi.
