Torque and preload with friction scatter

Calculate tightening torque and preload for hex head and socket head screws.
The calculation considers friction scatter, tool accuracy and scatter on preload.

Based on VDI 2230:2014

Screw type

Hex head	Socket head
ISO 4014/ISO 4017

Clearance hole - ISO 273

Fine Medium Coarse

Mechanical properties of material, thread size and friction

Property class of screw
Thread size
Utilization of yield strength %
Friction range
Thread friction value	Lower Upper
Nut/bolt head friction value	Lower Upper

Tool precision

Include tool precision

Data used in calculation

Yield strength Rp02	640 N/mm²
Thread pitch P	0.8 mm
Pitch diameter d2	4.48 mm
Root diameter d3	4.019 mm
Clearance hole dh	5.5 mm
Head bearing diameter dw	6.9 mm
Stress area As	14.2 mm²

Results

Maximum tightening torque MA	6.2 Nm
Maximum preload FM	7.6 kN
Minimum preload FM	kN
Minimum preload FM	kN
Minimum preload FM	kN
Difference	- %

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Friction coefficient test

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