The authors developed a special design of a rotary friction tool with a self-rotating cup cutter for rotary friction boring of large holes. This paper presents the results of parametric optimization of stressed components of the rotary friction tool by virtual experiments in ANSYS WB. The authors predicted the cutting force components at the worst position of the cup cutter, which was 20 degrees as contact forces in the process of boring a large diameter hole, and built a design model. Using the Johnson-Cook model as the failure criterion for the elements of the mesh, projections of the cutting forces resulting from the hole processing were obtained. The relation between input and output parameters (stresses) is established, optimization criteria are specified, and optimal parameters of the tool stresses components are chosen. It was also found that the averaged values of the force at the initial moment (cutting into the workpiece) change linearly, then becoming practically constant. The idea of parametric optimization consisted in carrying out several virtual experiments, in which the possible range of variation of the basic dimensions was indicated and the optimization criteria were set, the optimal parameters of the tool design were selected from the presented candidates. The optimization method bypasses the design cycle, which is costly and time-consuming due to prototype testing and subsequent refinement.