6.8 Bolt Torque Chart

Tightening torque and clamp force for Class 6.8 bolts from M1.6 to M64. For example, an M8 6.8 bolt needs about 19.9 N·m (14.7 ft·lb) with dry threads.

Medium-strength carbon steel, rarely stocked. Sits between general-purpose and high-strength classes.

Standard
Metric (ISO 898-1)
Yield strength used
480 MPa (70 ksi)
Tensile strength
600 MPa (87 ksi)
Sizes covered
M1.6 – M64
Class 6.8 — Coarse thread, tightening torque at 70% of yield
Size Threadpitch Clamp forcepreload Dryμ 0.15 Oiledμ 0.11 PTFE / moly pasteμ 0.06
M1.6 M1.6×0.350.35 mm 0.43 kN96 lbf 0.15 N·m0.11 ft·lb 0.12 N·m0.09 ft·lb 0.08 N·m0.06 ft·lb
M2 M2×0.40.4 mm 0.70 kN157 lbf 0.31 N·m0.23 ft·lb 0.24 N·m0.17 ft·lb 0.16 N·m0.12 ft·lb
M2.5 M2.5×0.450.45 mm 1.14 kN256 lbf 0.63 N·m0.46 ft·lb 0.47 N·m0.35 ft·lb 0.32 N·m0.23 ft·lb
M3 M3×0.50.5 mm 1.69 kN380 lbf 1.07 N·m0.79 ft·lb 0.81 N·m0.59 ft·lb 0.54 N·m0.40 ft·lb
M3.5 M3.5×0.60.6 mm 2.28 kN512 lbf 1.65 N·m1.22 ft·lb 1.24 N·m0.92 ft·lb 0.84 N·m0.62 ft·lb
M4 M4×0.70.7 mm 2.95 kN663 lbf 2.47 N·m1.82 ft·lb 1.86 N·m1.37 ft·lb 1.25 N·m0.92 ft·lb
M5 M5×0.80.8 mm 4.77 kN1071 lbf 4.79 N·m3.53 ft·lb 3.60 N·m2.66 ft·lb 2.42 N·m1.78 ft·lb
M6 M6×11 mm 6.76 kN1520 lbf 8.28 N·m6.11 ft·lb 6.24 N·m4.60 ft·lb 4.19 N·m3.09 ft·lb
M7 M7×11 mm 9.70 kN2180 lbf 13.4 N·m9.90 ft·lb 10.0 N·m7.41 ft·lb 6.68 N·m4.92 ft·lb
M8 M8×1.251.25 mm 12.3 kN2765 lbf 19.9 N·m14.7 ft·lb 15.0 N·m11.0 ft·lb 10.0 N·m7.38 ft·lb
M10 M10×1.51.5 mm 19.5 kN4380 lbf 39.0 N·m28.7 ft·lb 29.2 N·m21.6 ft·lb 19.5 N·m14.4 ft·lb
M12 M12×1.751.75 mm 28.3 kN6365 lbf 66.9 N·m49.3 ft·lb 50.1 N·m37.0 ft·lb 33.4 N·m24.6 ft·lb
M14 M14×22 mm 38.8 kN8720 lbf 106.3 N·m78.4 ft·lb 79.7 N·m58.8 ft·lb 53.0 N·m39.1 ft·lb
M16 M16×22 mm 52.6 kN11834 lbf 163.0 N·m120.2 ft·lb 121.5 N·m89.6 ft·lb 79.9 N·m59.0 ft·lb
M18 M18×2.52.5 mm 64.7 kN14539 lbf 227.7 N·m167.9 ft·lb 170.3 N·m125.6 ft·lb 113.0 N·m83.3 ft·lb
M20 M20×2.52.5 mm 82.3 kN18491 lbf 318.7 N·m235.0 ft·lb 237.5 N·m175.2 ft·lb 156.3 N·m115.3 ft·lb
M22 M22×2.52.5 mm 101.9 kN22917 lbf 434.8 N·m320.7 ft·lb 322.8 N·m238.1 ft·lb 210.9 N·m155.6 ft·lb
M24 M24×33 mm 118.4 kN26627 lbf 548.9 N·m404.9 ft·lb 409.1 N·m301.7 ft·lb 269.3 N·m198.6 ft·lb
M27 M27×33 mm 154.4 kN34702 lbf 805.8 N·m594.3 ft·lb 597.9 N·m441.0 ft·lb 390.1 N·m287.7 ft·lb
M30 M30×3.53.5 mm 188.4 kN42344 lbf 1096.6 N·m808.8 ft·lb 815.0 N·m601.1 ft·lb 533.5 N·m393.5 ft·lb
M33 M33×3.53.5 mm 233.0 kN52388 lbf 1476.1 N·m1088.7 ft·lb 1093.8 N·m806.8 ft·lb 711.6 N·m524.8 ft·lb
M36 M36×44 mm 274.4 kN61692 lbf 1903.4 N·m1403.8 ft·lb 1412.5 N·m1041.8 ft·lb 921.7 N·m679.8 ft·lb
M39 M39×44 mm 327.9 kN73704 lbf 2454.0 N·m1810.0 ft·lb 1816.5 N·m1339.8 ft·lb 1178.9 N·m869.5 ft·lb
M42 M42×4.54.5 mm 376.6 kN84669 lbf 3045.7 N·m2246.4 ft·lb 2257.5 N·m1665.0 ft·lb 1469.3 N·m1083.7 ft·lb
M45 M45×4.54.5 mm 438.8 kN98650 lbf 3789.6 N·m2795.1 ft·lb 2802.8 N·m2067.2 ft·lb 1815.9 N·m1339.4 ft·lb
M48 M48×55 mm 495.0 kN111275 lbf 4590.5 N·m3385.8 ft·lb 3398.9 N·m2506.9 ft·lb 2207.3 N·m1628.0 ft·lb
M52 M52×55 mm 590.6 kN132779 lbf 5874.0 N·m4332.5 ft·lb 4339.5 N·m3200.7 ft·lb 2805.0 N·m2068.9 ft·lb
M56 M56×5.55.5 mm 682.1 kN153339 lbf 7327.1 N·m5404.2 ft·lb 5416.1 N·m3994.7 ft·lb 3505.0 N·m2585.2 ft·lb
M60 M60×5.55.5 mm 793.6 kN178417 lbf 9058.1 N·m6680.9 ft·lb 6683.2 N·m4929.2 ft·lb 4308.3 N·m3177.6 ft·lb
M64 M64×66 mm 899.1 kN202132 lbf 10912.5 N·m8048.6 ft·lb 8057.6 N·m5943.0 ft·lb 5202.6 N·m3837.3 ft·lb
Class 6.8 — Fine thread, tightening torque at 70% of yield
Size Threadpitch Clamp forcepreload Dryμ 0.15 Oiledμ 0.11 PTFE / moly pasteμ 0.06
M1.6 M1.6×0.20.2 mm 0.53 kN118 lbf 0.18 N·m0.13 ft·lb 0.13 N·m0.10 ft·lb 0.09 N·m0.06 ft·lb
M2 M2×0.250.25 mm 0.82 kN185 lbf 0.35 N·m0.26 ft·lb 0.26 N·m0.19 ft·lb 0.17 N·m0.13 ft·lb
M2.5 M2.5×0.350.35 mm 1.24 kN280 lbf 0.67 N·m0.50 ft·lb 0.50 N·m0.37 ft·lb 0.33 N·m0.24 ft·lb
M3 M3×0.350.35 mm 1.88 kN423 lbf 1.17 N·m0.86 ft·lb 0.86 N·m0.64 ft·lb 0.56 N·m0.42 ft·lb
M3.5 M3.5×0.350.35 mm 2.65 kN597 lbf 1.85 N·m1.37 ft·lb 1.37 N·m1.01 ft·lb 0.88 N·m0.65 ft·lb
M4 M4×0.50.5 mm 3.29 kN740 lbf 2.68 N·m1.98 ft·lb 1.99 N·m1.47 ft·lb 1.31 N·m0.96 ft·lb
M5 M5×0.50.5 mm 5.42 kN1218 lbf 5.28 N·m3.89 ft·lb 3.90 N·m2.88 ft·lb 2.52 N·m1.86 ft·lb
M6 M6×0.750.75 mm 7.40 kN1664 lbf 8.88 N·m6.55 ft·lb 6.61 N·m4.87 ft·lb 4.34 N·m3.20 ft·lb
M7 M7×0.750.75 mm 10.5 kN2352 lbf 14.2 N·m10.5 ft·lb 10.5 N·m7.76 ft·lb 6.85 N·m5.05 ft·lb
M8 M8×11 mm 13.2 kN2959 lbf 21.0 N·m15.5 ft·lb 15.6 N·m11.5 ft·lb 10.3 N·m7.56 ft·lb
M10 M10×1.251.25 mm 20.6 kN4623 lbf 40.6 N·m29.9 ft·lb 30.2 N·m22.3 ft·lb 19.9 N·m14.7 ft·lb
M12 M12×1.51.5 mm 29.6 kN6657 lbf 69.2 N·m51.0 ft·lb 51.5 N·m38.0 ft·lb 33.9 N·m25.0 ft·lb
M14 M14×1.51.5 mm 41.8 kN9408 lbf 112.5 N·m83.0 ft·lb 83.4 N·m61.5 ft·lb 54.3 N·m40.1 ft·lb
M16 M16×1.51.5 mm 56.2 kN12633 lbf 171.0 N·m126.1 ft·lb 126.3 N·m93.1 ft·lb 81.5 N·m60.1 ft·lb
M18 M18×1.51.5 mm 72.7 kN16333 lbf 248.2 N·m183.0 ft·lb 182.6 N·m134.7 ft·lb 117.1 N·m86.3 ft·lb
M20 M20×1.51.5 mm 91.2 kN20508 lbf 343.9 N·m253.6 ft·lb 252.4 N·m186.2 ft·lb 160.9 N·m118.7 ft·lb
M22 M22×1.51.5 mm 111.9 kN25158 lbf 465.6 N·m343.4 ft·lb 340.9 N·m251.5 ft·lb 216.3 N·m159.5 ft·lb
M24 M24×22 mm 129.2 kN29037 lbf 585.1 N·m431.5 ft·lb 430.6 N·m317.6 ft·lb 276.1 N·m203.7 ft·lb
M27 M27×22 mm 166.6 kN37446 lbf 852.1 N·m628.5 ft·lb 625.2 N·m461.1 ft·lb 398.2 N·m293.7 ft·lb
M30 M30×22 mm 208.7 kN46923 lbf 1182.4 N·m872.1 ft·lb 865.5 N·m638.3 ft·lb 548.5 N·m404.6 ft·lb
M33 M33×22 mm 255.6 kN57468 lbf 1579.1 N·m1164.7 ft·lb 1153.7 N·m851.0 ft·lb 728.4 N·m537.2 ft·lb
M36 M36×33 mm 290.6 kN65334 lbf 1985.3 N·m1464.3 ft·lb 1460.9 N·m1077.5 ft·lb 936.5 N·m690.8 ft·lb
M39 M39×33 mm 345.5 kN77680 lbf 2550.2 N·m1881.0 ft·lb 1872.9 N·m1381.4 ft·lb 1195.5 N·m881.7 ft·lb
M42 M42×33 mm 405.2 kN91094 lbf 3213.2 N·m2369.9 ft·lb 2355.6 N·m1737.4 ft·lb 1498.0 N·m1104.9 ft·lb
M45 M45×33 mm 469.6 kN105576 lbf 3982.0 N·m2936.9 ft·lb 2914.8 N·m2149.8 ft·lb 1847.6 N·m1362.7 ft·lb
M48 M48×33 mm 538.8 kN121126 lbf 4884.1 N·m3602.4 ft·lb 3570.1 N·m2633.2 ft·lb 2256.0 N·m1663.9 ft·lb
M52 M52×44 mm 614.3 kN138098 lbf 6045.0 N·m4458.6 ft·lb 4439.4 N·m3274.3 ft·lb 2833.7 N·m2090.1 ft·lb
M56 M56×44 mm 720.4 kN161945 lbf 7625.3 N·m5624.1 ft·lb 5590.0 N·m4123.0 ft·lb 3554.7 N·m2621.8 ft·lb
M60 M60×44 mm 834.9 kN187691 lbf 9397.8 N·m6931.5 ft·lb 6879.8 N·m5074.3 ft·lb 4361.8 N·m3217.1 ft·lb
M64 M64×44 mm 957.9 kN215336 lbf 11424.8 N·m8426.5 ft·lb 8353.3 N·m6161.1 ft·lb 5281.8 N·m3895.6 ft·lb

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 an M8 6.8 bolt?

About 19.9 N·m (14.7 ft·lb) with dry threads and 15.0 N·m (11.0 ft·lb) with oiled threads (M8×1.25, 70% of yield, clamp force 12.3 kN).

What is the torque for an M10 6.8 bolt?

About 39.0 N·m (28.7 ft·lb) with dry threads and 29.2 N·m (21.6 ft·lb) with oiled threads (M10×1.5, 70% of yield, clamp force 19.5 kN).

What is the torque for an M12 6.8 bolt?

About 66.9 N·m (49.3 ft·lb) with dry threads and 50.1 N·m (37.0 ft·lb) with oiled threads (M12×1.75, 70% of yield, clamp force 28.3 kN).

Other grades

4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9 Grade 2 Grade 5 Grade 8 A307 A325 A490 A574 A2-70 A4-70 A4-80
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