ASTM A574 Bolt Torque Chart
Tightening torque and clamp force for ASTM A574 bolts from #1 to 2". For example, a 1/4" A574 bolt needs about 14.7 ft·lb (20.0 N·m) with dry threads.
Alloy steel socket head cap screws, the inch counterpart of ISO 12.9. Yield of 150 ksi is assumed (the standard specifies tensile and proof load).
- Standard
- ASTM (inch)
- Yield strength used
- 1034 MPa (150 ksi)
- Tensile strength
- 1241 MPa (180 ksi)
- Sizes covered
- #1 – 2"
| Size | Threadpitch | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|---|
| #1 | 1-64 UNC64 TPI | 1.22 kN275 lbf | 4.40 in·lb0.50 N·m | 3.34 in·lb0.38 N·m | 2.29 in·lb0.26 N·m |
| #2 | 2-56 UNC56 TPI | 1.73 kN388 lbf | 7.20 in·lb0.81 N·m | 5.47 in·lb0.62 N·m | 3.74 in·lb0.42 N·m |
| #3 | 3-48 UNC48 TPI | 2.27 kN511 lbf | 10.8 in·lb1.22 N·m | 8.24 in·lb0.93 N·m | 5.64 in·lb0.64 N·m |
| #4 | 4-40 UNC40 TPI | 2.82 kN633 lbf | 15.2 in·lb1.72 N·m | 11.6 in·lb1.31 N·m | 8.00 in·lb0.90 N·m |
| #5 | 5-40 UNC40 TPI | 3.71 kN835 lbf | 22.0 in·lb2.49 N·m | 16.7 in·lb1.89 N·m | 11.4 in·lb1.29 N·m |
| #6 | 6-32 UNC32 TPI | 4.24 kN954 lbf | 28.0 in·lb3.16 N·m | 21.4 in·lb2.42 N·m | 14.8 in·lb1.67 N·m |
| #8 | 8-32 UNC32 TPI | 6.54 kN1471 lbf | 50.1 in·lb5.66 N·m | 37.9 in·lb4.29 N·m | 25.8 in·lb2.91 N·m |
| #10 | 10-24 UNC24 TPI | 8.19 kN1840 lbf | 73.3 in·lb8.28 N·m | 56.0 in·lb6.32 N·m | 38.6 in·lb4.36 N·m |
| #12 | 12-24 UNC24 TPI | 11.3 kN2537 lbf | 112.9 in·lb12.8 N·m | 85.7 in·lb9.68 N·m | 58.4 in·lb6.60 N·m |
| 1/4" | 1/4"-20 UNC20 TPI | 14.9 kN3341 lbf | 14.7 ft·lb20.0 N·m | 11.2 ft·lb15.2 N·m | 7.63 ft·lb10.3 N·m |
| 5/16" | 5/16"-18 UNC18 TPI | 24.5 kN5504 lbf | 29.1 ft·lb39.4 N·m | 22.0 ft·lb29.8 N·m | 14.9 ft·lb20.2 N·m |
| 3/8" | 3/8"-16 UNC16 TPI | 36.2 kN8135 lbf | 50.2 ft·lb68.1 N·m | 37.9 ft·lb51.3 N·m | 25.5 ft·lb34.6 N·m |
| 7/16" | 7/16"-14 UNC14 TPI | 49.6 kN11160 lbf | 79.0 ft·lb107.0 N·m | 59.5 ft·lb80.7 N·m | 40.1 ft·lb54.4 N·m |
| 1/2" | 1/2"-13 UNC13 TPI | 66.3 kN14896 lbf | 122.7 ft·lb166.3 N·m | 92.2 ft·lb125.0 N·m | 61.7 ft·lb83.6 N·m |
| 9/16" | 9/16"-12 UNC12 TPI | 85.0 kN19100 lbf | 174.1 ft·lb236.1 N·m | 130.7 ft·lb177.2 N·m | 87.3 ft·lb118.3 N·m |
| 5/8" | 5/8"-11 UNC11 TPI | 105.5 kN23725 lbf | 242.0 ft·lb328.1 N·m | 181.4 ft·lb246.0 N·m | 120.8 ft·lb163.8 N·m |
| 3/4" | 3/4"-10 UNC10 TPI | 156.2 kN35111 lbf | 425.7 ft·lb577.1 N·m | 318.0 ft·lb431.2 N·m | 210.4 ft·lb285.3 N·m |
| 7/8" | 7/8"-9 UNC9 TPI | 215.6 kN48472 lbf | 681.7 ft·lb924.2 N·m | 508.4 ft·lb689.3 N·m | 335.2 ft·lb454.4 N·m |
| 1" | 1"-8 UNC8 TPI | 282.9 kN63590 lbf | 1019.2 ft·lb1381.9 N·m | 759.8 ft·lb1030.1 N·m | 500.3 ft·lb678.4 N·m |
| 1-1/8" | 1-1/8"-7 UNC7 TPI | 356.4 kN80127 lbf | 1444.5 ft·lb1958.4 N·m | 1077.5 ft·lb1460.8 N·m | 710.5 ft·lb963.3 N·m |
| 1-1/4" | 1-1/4"-7 UNC7 TPI | 452.5 kN101735 lbf | 2021.5 ft·lb2740.8 N·m | 1502.3 ft·lb2036.8 N·m | 983.0 ft·lb1332.8 N·m |
| 1-3/8" | 1-3/8"-6 UNC6 TPI | 539.3 kN121237 lbf | 2657.7 ft·lb3603.3 N·m | 1979.2 ft·lb2683.4 N·m | 1300.7 ft·lb1763.5 N·m |
| 1-1/2" | 1-1/2"-6 UNC6 TPI | 656.2 kN147521 lbf | 3505.8 ft·lb4753.2 N·m | 2602.9 ft·lb3529.1 N·m | 1700.1 ft·lb2305.0 N·m |
| 1-3/4" | 1-3/4"-5 UNC5 TPI | 887.0 kN199402 lbf | 5531.8 ft·lb7500.1 N·m | 4111.3 ft·lb5574.2 N·m | 2690.8 ft·lb3648.3 N·m |
| 2" | 2"-4.5 UNC4.5 TPI | 1166.6 kN262259 lbf | 8293.2 ft·lb11244.1 N·m | 6158.0 ft·lb8349.1 N·m | 4022.7 ft·lb5454.0 N·m |
| Size | Threadpitch | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|---|
| #1 | 1-72 UNF72 TPI | 1.30 kN292 lbf | 4.60 in·lb0.52 N·m | 3.48 in·lb0.39 N·m | 2.36 in·lb0.27 N·m |
| #2 | 2-64 UNF64 TPI | 1.84 kN413 lbf | 7.57 in·lb0.85 N·m | 5.71 in·lb0.65 N·m | 3.85 in·lb0.44 N·m |
| #3 | 3-56 UNF56 TPI | 2.44 kN549 lbf | 11.5 in·lb1.30 N·m | 8.66 in·lb0.98 N·m | 5.85 in·lb0.66 N·m |
| #4 | 4-48 UNF48 TPI | 3.08 kN693 lbf | 16.3 in·lb1.85 N·m | 12.4 in·lb1.40 N·m | 8.37 in·lb0.95 N·m |
| #5 | 5-44 UNF44 TPI | 3.88 kN872 lbf | 22.8 in·lb2.57 N·m | 17.2 in·lb1.94 N·m | 11.6 in·lb1.31 N·m |
| #6 | 6-40 UNF40 TPI | 4.74 kN1065 lbf | 30.6 in·lb3.45 N·m | 23.1 in·lb2.61 N·m | 15.6 in·lb1.76 N·m |
| #8 | 8-36 UNF36 TPI | 6.88 kN1546 lbf | 52.1 in·lb5.88 N·m | 39.2 in·lb4.43 N·m | 26.4 in·lb2.98 N·m |
| #10 | 10-32 UNF32 TPI | 9.34 kN2099 lbf | 81.3 in·lb9.19 N·m | 61.2 in·lb6.91 N·m | 41.1 in·lb4.64 N·m |
| #12 | 12-28 UNF28 TPI | 12.0 kN2707 lbf | 118.9 in·lb13.4 N·m | 89.5 in·lb10.1 N·m | 60.1 in·lb6.79 N·m |
| 1/4" | 1/4"-28 UNF28 TPI | 17.0 kN3818 lbf | 16.4 ft·lb22.2 N·m | 12.2 ft·lb16.6 N·m | 8.10 ft·lb11.0 N·m |
| 5/16" | 5/16"-24 UNF24 TPI | 27.1 kN6096 lbf | 31.5 ft·lb42.7 N·m | 23.5 ft·lb31.9 N·m | 15.5 ft·lb21.0 N·m |
| 3/8" | 3/8"-24 UNF24 TPI | 41.0 kN9220 lbf | 55.2 ft·lb74.9 N·m | 41.0 ft·lb55.6 N·m | 26.8 ft·lb36.3 N·m |
| 7/16" | 7/16"-20 UNF20 TPI | 55.4 kN12463 lbf | 85.8 ft·lb116.4 N·m | 63.8 ft·lb86.5 N·m | 41.8 ft·lb56.7 N·m |
| 1/2" | 1/2"-20 UNF20 TPI | 74.7 kN16792 lbf | 134.3 ft·lb182.1 N·m | 99.4 ft·lb134.7 N·m | 64.4 ft·lb87.3 N·m |
| 9/16" | 9/16"-18 UNF18 TPI | 94.8 kN21309 lbf | 189.1 ft·lb256.4 N·m | 139.9 ft·lb189.6 N·m | 90.6 ft·lb122.9 N·m |
| 5/8" | 5/8"-18 UNF18 TPI | 119.5 kN26870 lbf | 265.8 ft·lb360.4 N·m | 195.9 ft·lb265.7 N·m | 126.1 ft·lb171.0 N·m |
| 3/4" | 3/4"-16 UNF16 TPI | 174.2 kN39153 lbf | 461.9 ft·lb626.2 N·m | 339.9 ft·lb460.9 N·m | 218.0 ft·lb295.5 N·m |
| 7/8" | 7/8"-14 UNF14 TPI | 237.9 kN53484 lbf | 733.7 ft·lb994.7 N·m | 539.7 ft·lb731.7 N·m | 345.7 ft·lb468.8 N·m |
| 1" | 1"-12 UNF12 TPI | 309.6 kN69605 lbf | 1090.3 ft·lb1478.3 N·m | 802.5 ft·lb1088.1 N·m | 514.8 ft·lb697.9 N·m |
| 1-1/8" | 1-1/8"-12 UNF12 TPI | 399.6 kN89832 lbf | 1572.8 ft·lb2132.4 N·m | 1154.3 ft·lb1565.0 N·m | 735.9 ft·lb997.7 N·m |
| 1-1/4" | 1-1/4"-12 UNF12 TPI | 501.0 kN112636 lbf | 2179.6 ft·lb2955.2 N·m | 1596.0 ft·lb2163.8 N·m | 1012.3 ft·lb1372.5 N·m |
| 1-3/8" | 1-3/8"-12 UNF12 TPI | 613.9 kN138016 lbf | 2925.2 ft·lb3966.0 N·m | 2137.7 ft·lb2898.3 N·m | 1350.3 ft·lb1830.7 N·m |
| 1-1/2" | 1-1/2"-12 UNF12 TPI | 738.3 kN165973 lbf | 3823.6 ft·lb5184.1 N·m | 2789.8 ft·lb3782.4 N·m | 1755.9 ft·lb2380.7 N·m |
Preload is 70% of yield. Torque per ISO 16047 / VDI 2230 for standard hex heads, with the same friction μ in the threads and under the head. Click a size for wrench size, tap drill and a worked example. Always follow the manufacturer's value where one exists.
Frequently asked questions
What is the torque for a 1/4" A574 bolt?
About 14.7 ft·lb (20.0 N·m) with dry threads and 11.2 ft·lb (15.2 N·m) with oiled threads (1/4"-20 UNC, 70% of yield, clamp force 14.9 kN).
What is the torque for a 3/8" A574 bolt?
About 50.2 ft·lb (68.1 N·m) with dry threads and 37.9 ft·lb (51.3 N·m) with oiled threads (3/8"-16 UNC, 70% of yield, clamp force 36.2 kN).
What is the torque for a 1/2" A574 bolt?
About 122.7 ft·lb (166.3 N·m) with dry threads and 92.2 ft·lb (125.0 N·m) with oiled threads (1/2"-13 UNC, 70% of yield, clamp force 66.3 kN).