Metric Fine Thread Torque Chart — 8.8, 10.9 and 12.9
Starting assembly torque for ISO 898-1 metric bolts, calculated from T = K × D × F with the clamp load F set at 75% of proof load. Dry uses K = 0.20; lubricated uses K = 0.15. Switch units below.
Not for structural A325 / A490 joints. Match dry or lubricated to the bolt as it is installed.
Torque (N·m)
| Size | 8.8 dry | 10.9 dry | 12.9 dry | 8.8 lubricated | 10.9 lubricated | 12.9 lubricated |
|---|---|---|---|---|---|---|
| M8 x 1 | 27 | 39 | 46 | 20 | 29 | 34 |
| M10 x 1.25 | 53 | 76 | 89 | 40 | 57 | 67 |
| M10 x 1 | 56 | 80 | 94 | 42 | 60 | 70 |
| M12 x 1.5 | 92 | 132 | 154 | 69 | 99 | 115 |
| M12 x 1.25 | 96 | 138 | 161 | 72 | 103 | 121 |
| M14 x 1.5 | 152 | 217 | 254 | 114 | 163 | 190 |
| M16 x 1.5 | 233 | 333 | 389 | 175 | 250 | 292 |
| M18 x 1.5 | 350 | 485 | 566 | 263 | 363 | 425 |
| M20 x 1.5 | 489 | 676 | 790 | 367 | 507 | 593 |
| M22 x 1.5 | 659 | 912 | 1,066 | 495 | 684 | 800 |
| M24 x 2 | 830 | 1,149 | 1,342 | 623 | 861 | 1,007 |
| M27 x 2 | 1,205 | 1,666 | 1,948 | 903 | 1,250 | 1,461 |
| M30 x 2 | 1,677 | 2,320 | 2,712 | 1,258 | 1,740 | 2,034 |
| M33 x 2 | 2,260 | 3,126 | 3,653 | 1,695 | 2,344 | 2,740 |
| M36 x 3 | 2,802 | 3,877 | 4,531 | 2,102 | 2,907 | 3,398 |
Class 8.8 proof stress is 580 MPa up to M16 and 600 MPa above. Class 9.8 and the low classes are not shown. Pair with nut class 8 / 10 / 12.
Do not use these values for pretensioned or slip-critical structural joints (ASTM F3125 A325 / A490 under RCSC). Those are installed by turn-of-nut, calibrated wrench, twist-off or DTI methods.
Lubrication changes the answer. Applying a dry value to a lubricated, plated or anti-seized bolt can yield or break it. The manufacturer’s or engineer’s value always governs.
How to read this chart: find the size, pick the grade, then pick dry or lubricated to match the bolt as it will actually go in. Worked example — M10 × 1.5 class 8.8, dry: stress area 58.0 mm² × 580 MPa proof = 33.6 kN proof load. Clamp at 75% = 25.2 kN. T = 0.20 × 0.010 m × 25,230 N = 50 N·m (37 ft-lb). Oiled (K 0.15): 38 N·m.
Stress area, proof load and clamp load
| Size | Stress area (mm²) | 8.8 proof load (kN) | 8.8 clamp, 75% (kN) | 10.9 proof load (kN) | 10.9 clamp, 75% (kN) | 12.9 proof load (kN) | 12.9 clamp, 75% (kN) |
|---|---|---|---|---|---|---|---|
| M8 x 1 | 39.2 | 22.7 | 17.0 | 32.5 | 24.4 | 38.0 | 28.5 |
| M10 x 1.25 | 61.2 | 35.5 | 26.6 | 50.8 | 38.1 | 59.4 | 44.5 |
| M10 x 1 | 64.5 | 37.4 | 28.1 | 53.5 | 40.1 | 62.6 | 46.9 |
| M12 x 1.5 | 88.1 | 51.1 | 38.3 | 73.1 | 54.9 | 85.5 | 64.1 |
| M12 x 1.25 | 92.1 | 53.4 | 40.1 | 76.4 | 57.3 | 89.3 | 67.0 |
| M14 x 1.5 | 124.5 | 72.2 | 54.2 | 103.4 | 77.5 | 120.8 | 90.6 |
| M16 x 1.5 | 167.2 | 97.0 | 72.8 | 138.8 | 104.1 | 162.2 | 121.7 |
| M18 x 1.5 | 216.2 | 129.7 | 97.3 | 179.5 | 134.6 | 209.7 | 157.3 |
| M20 x 1.5 | 271.5 | 162.9 | 122.2 | 225.3 | 169.0 | 263.4 | 197.5 |
| M22 x 1.5 | 333.1 | 199.8 | 149.9 | 276.4 | 207.3 | 323.1 | 242.3 |
| M24 x 2 | 384.4 | 230.6 | 173.0 | 319.1 | 239.3 | 372.9 | 279.7 |
| M27 x 2 | 495.7 | 297.4 | 223.1 | 411.5 | 308.6 | 480.9 | 360.7 |
| M30 x 2 | 621.2 | 372.7 | 279.5 | 515.6 | 386.7 | 602.6 | 451.9 |
| M33 x 2 | 760.8 | 456.5 | 342.4 | 631.5 | 473.6 | 738.0 | 553.5 |
| M36 x 3 | 864.9 | 519.0 | 389.2 | 717.9 | 538.4 | 839.0 | 629.2 |
K factor: the number that moves the answer
| Condition | Typical K | Note |
|---|---|---|
| Plain steel, dry, as received | 0.20 | This chart’s dry column |
| Zinc plated, dry | 0.17 – 0.22 | Varies with plating and topcoat; many sealers add lubricity |
| Light machine oil | 0.15 – 0.18 | This chart’s lubricated column uses 0.15 |
| Moly paste or anti-seize | 0.10 – 0.13 | Big drop — a dry value here can yield the bolt |
| Stainless on stainless, dry | 0.25 – 0.35 | Galling risk: use anti-seize and tighten slowly |
Typical ranges only. Actual K depends on finish, lubricant, washer, speed and even the batch — test critical joints.
Chart torque converts to actual preload with a scatter of about ±25–30%, because friction varies. Thread-forming and thread-cutting screws have no universal torque — test on the actual joint. Published hex-bolt values are not automatically valid for socket head cap screws.
