The purpose of this work is to carry out a research started some years ago and concerning the evaluation of the releasing moments in conical steel couplings realised with the simultaneous presence of interference and anaerobic adhesive (Loctite 638). The investigation was particularly focused on the effects due to the adhesive defect density and the interference level. The releasing tests have been performed in accordance with the Design of Experimental methodology. Therefore, a factorial experiment was designed with two parameters (interference and adhesive defect density) on different levels, with the goals to evaluate the significance of the main and of the interaction effects and to determine the mathematical model of the failure load by applying the Analysis of Variance and the Fisher’s test to the results.