This paper describes a developed new method of body parts force displacements calculation of metal-cutting machine tools using combination of CAD and CAE technologies. It was carried out the analysis of analytical methods and the method of finite elements of body parts force displacements calculation of metal-cutting machine tools. On the basis of it the requirements to the method of calculation of compound errors of processing and deviations of the form of the processed surfaces due to deformations of the body parts of metal-cutting machines are established. The method of designing metal-cutting machines is grounded, which is based on mathematical modeling of different processes. It gives an opportunity to evaluate the accuracy of the machine and the impact on it of the individual assembly already in the initial stages of designing. The calculation methodology was implemented using ANSYS finite element analysis. This technique was used in the calculations on the example of high-precision lathes.