Bolt Tightening Torque
A REFERENCE tightening-torque table by thread size. Pick the series matching the material/application (0.5T for copper/aluminium/plastic bodies and electronics; T for plain steel), then cross-check the bolt class. Critical joints must follow the maker's spec or the standard.
Unit: 1 N·m = 10.2 kgf·cm (1 kgf·cm = 0.0981 N·m). The class table uses T ≈ K·d·F with K ≈ 0.2 (dry) and preload ≈ 90% of yield.
T-series — M1→M42 (N·m); PCB/electronics use 0.5T| Size | T (base) (N·m) | 0.5T (electronics) (N·m) | 1.8T (vehicle) (N·m) | 2.4T (construction) (N·m) |
|---|
| M1 | 0.0195 | 0.0098 | 0.035 | 0.047 |
| (M1.1) | 0.027 | 0.0135 | 0.049 | 0.065 |
| M1.2 | 0.037 | 0.0185 | 0.066 | 0.088 |
| (M1.4) | 0.058 | 0.029 | 0.104 | 0.14 |
| M1.6 | 0.086 | 0.043 | 0.156 | 0.205 |
| (M1.8) | 0.128 | 0.064 | 0.23 | 0.305 |
| M2 | 0.176 | 0.088 | 0.315 | 0.42 |
| (M2.2) | 0.23 | 0.116 | 0.41 | 0.55 |
| M2.5 | 0.36 | 0.18 | 0.65 | 0.86 |
| M3 | 0.63 | 0.315 | 1.14 | 1.5 |
| (M3.5) | 1 | 0.5 | 1.8 | 2.4 |
| M4 | 1.5 | 0.76 | 2.7 | 3.6 |
| (M4.5) | 2.15 | 1.08 | 3.9 | 5.2 |
| M5 | 3 | 1.5 | 5.4 | 7.2 |
| M6 | 5.2 | 2.6 | 9.2 | 12.2 |
| (M7) | 8.4 | 4.2 | 15 | 20 |
| M8 | 12.5 | 6.2 | 22 | 29.5 |
| M10 | 24.5 | 12.5 | 44 | 59 |
| M12 | 42 | 21 | 76 | 100 |
| M14 | 68 | 34 | 122 | 166 |
| M16 | 106 | 53 | 190 | 255 |
| (M18) | 146 | 73 | 270 | 350 |
| M20 | 204 | 102 | 370 | 490 |
| (M22) | 282 | 140 | 500 | 670 |
| M24 | 360 | 180 | 650 | 860 |
| (M27) | 520 | 260 | 940 | 1240 |
| M30 | 700 | 350 | 1260 | 1700 |
| (M33) | 960 | 480 | 1750 | 2300 |
| M36 | 1240 | 620 | 2250 | 3000 |
| (M39) | 1600 | 800 | 2900 | 3800 |
| M42 | 2000 | 1000 | 3600 | 4800 |
What each series is for| Series | Property class | Joint material | Application |
|---|
| T | 4.6~6.8 | Plain steel: SS · SC · SUS | General bolts & screws (一般) |
| 0.5T | — | Brass (黄銅), copper (銅), aluminium (アルミ), plastic | Electronics — PCB, soft joint bodies (電子製品) |
| 1.8T | 8.8~12.9 | Special steel: SCr · SNC · SCM | Vehicles, engines (車両・エンジン) |
| 2.4T | 10.9~12.9 | SCr · SNC · SCM · SNCM; high-tension bolts | Construction (建設) |
By property class — dry, K≈0.2 (Nm)| Size | Stress area As (mm²) | Class 8.8 (Nm) | Class 10.9 (Nm) | Class 12.9 (Nm) |
|---|
| M5 | 14.2 | 5.8 | 8.5 | 9.9 |
| M6 | 20.1 | 10 | 14 | 17 |
| M8 | 36.6 | 25 | 35 | 41 |
| M10 | 58.0 | 49 | 69 | 83 |
| M12 | 84.3 | 85 | 120 | 145 |
| M14 | 115 | 135 | 190 | 230 |
| M16 | 157 | 210 | 295 | 355 |
| M18 | 192 | 290 | 405 | 485 |
| M20 | 245 | 410 | 580 | 690 |
| M22 | 303 | 550 | 780 | 930 |
| M24 | 353 | 710 | 1000 | 1200 |
⚠ REFERENCE values. T-series: T = base (plain steel, general use); 0.5T = soft joint bodies (brass/copper/aluminium/plastic) → electronics, PCB; 1.8T = special steel (vehicle/engine); 2.4T = high-strength (construction). Lubrication/plating change torque a lot (lube cuts ~20–30%). Two cells, M1 and M1.8 in the T column, are misprinted in the source (0.00195 / 0.0128); cross-checking the 0.5T·1.8T·2.4T columns shows the correct values are 0.0195 / 0.128 — the consistent values are used. For critical, dynamic or safety joints follow the maker's spec or the standard (VDI 2230, JIS B1083). Do not use as the final basis without verification.
Frequently asked questions
Which column for PCB / electronics bolts?
Use the 0.5T column — for soft joint bodies (brass, copper, aluminium, plastic) as in electronics/PCB, to avoid stripping the soft thread.
Do lubrication or plating change the torque?
Yes, significantly. The table assumes a dry thread (K≈0.2); lubrication reduces the required torque by roughly 20–30% for the same preload.
How do I get clamp force from torque?
Use the “Bolt torque ↔ clamp force” calculator under Calculators: enter thread size, class, K and torque to get the clamp force and stress.
MINATA — minatavn.com