This paper presents an analytical model for calculating the cutting parameters plastic metal alloys using an end mill, which ensure the mechanical strength of load-bearing structure elements. This model can be used to analyze cutting forces in vertical feed. The model is based on the analytical model of oblique cutting. The analysis is carried out by the energy method, taking into account the power spent on the formation of new surfaces during cutting. The cutting process is considered as a process of continuous plastic deformation of a material with deformation hardening. The predictions cutting forces of this analytical model are compared with experimental results for a 45 steel (equivalent to AISI 1045 steel) as an example. The end cutting tests were performed on a vertical 3-axis milling machine. A Kistler (model 9272) dynamometer was used to measure cutting forces. The results showed good agreement between the theoretically predicted and experimentally measured cutting forces.