Torque and Preload Calculator

Calculate tightening torque, preload and surface pressure for hex head and socket head screws.

Based on VDI 2230:2014

Data Property Class Thread Size Utilization of Yield Strength % Thread Friction Value Nut/Bolt Head Friction Value

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	14.183	mm²

Result

Maximum allowable tightening torque:	6.17	Nm
Maximum possible preload:	7.60	kN
Maximum surface pressure under screw head/nut:	557.59	N/mm²

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