AbstractThe Gough test data on fatigue under combined bending and twisting with superimposed mean bending and torsion stresses with and without stress raisers has been re‐investigated in terms of the stresses acting on the plane of maximum range of shear stress. It has been shown that the allowable amplitude of shear stress on this plane can be predicted from an equation of the formτa= [t ‐ c1(Kt×σa)1.5−c2σ2m]/Ktwhere σaand σmare the normal stress amplitude and mean normal stress respectively on the plane of maximum range of shear stress, c1and c2are defined material constants and Ktis the theoretical stress concentra