Metric Tightening Torques

Metric Tightening Torques


The friction values can vary depending on many factors: material pairing, the surface quality (peak to valley heights), the surface treatment and the type of lubrication. Therefore this information is only meant as a guide


Thread Diameter Friction Coefficient Tightening Torque M (Nm) Property Class
50 70 80
M1.6 0.1 0.1 0.1 0.2
M2 0.1 0.15 0.2 0.3
M2.5 0.1 0.25 0.45 0.6
M3 0.1 0.85 1 1.3
M4 0.1 0.8 1.7 2.3
M5 0.1 1.6 3.4 4.6
M6 0.1 2.8 5.9 8
M8 0.1 6.8 14.5 19.3
M10 0.1 13.7 30 39.4
M12 0.1 23.3 50 67
M14 0.1 37.1 79 106
M16 0.1 56 121 161
M18 0.1 81 174 232
M20 0.1 114 244 325
M22 0.1 154 182
M24 0.1 197 234
M27 0.1 275 328
M30 0.1 374 445
M33 0.1 506
M36 0.1 651
M39 0.1 842

Note: Stainless steel fasteners tend to seize whilst being assembled (tightened). The risk of seizing is alleviated by:

Impact wrenches are not recommended for torquing 300 series stainless steel fasteners.

The tightening torques as stated above result in a 90% utilization of the yield strength.

Conversion Factor:

  • Nm to foot pound = 0.7376
  • Nm to inch pound = 8,851

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