Researches of assembly processes of cylindrical parts set by interference fit resulted in defining the admissible failure on mutual layout of detail axes in the position of assembly, which provides the range of basing schema needed for accuracy and the choice of methods to reach assembly accuracy. In this article a mathematical model for defining the durability of the contact of cylindrical details set by interference was developed, and that provides the possibility to determine the admissible external force, which in practice is mainly connection-oriented eccentrically to its axes.