Methods for experimental and computational assessment of the dissipation indicators of the endurance limit and cyclic durability of power lugs of machines and mechanisms are presented. Based on a generalization of the results of fatigue tests, the dependences of the standard deviation of the logarithm of the number of cycles before failure of lugs made of high-strength steels on the maximum amplitudes of cyclic stresses were constructed. Formulas are obtained for calculating the coefficient of variation of the theoretical stress concentration coefficient of the lugs from production deviations of their dimensions in plan and from the dispersion of the gap between the bolt and the hole. Based on these formulas, the values of the coefficient of variation of the theoretical stress concentration coefficient for typical lugs are obtained and given.