The method of counting allowances is created by prof. V. M. Kovan more than 40 years ago. Therefore today, when computers are used, it is possible to estimate more deeply the components of allowances and in that way it is possible to make the method of counting more accurate. The research object: it is a theoretical character job, which include dependent on such factors as: material solidity and of used up instrument. The purpose of the paper the allowance size depends on the production cost. The increase of allowance size, it will increase metal outlay, cost on cutting tool, electrical power, and so on. However on decrease of allowance size it will depend on worse detail waster percent and in some case the netting tool will work in malevolence conditions. So it’s very important to calculate allowance size. The elastic deformations of technological system which appear because the hardness of the material changes and because the machining tool wears mechanically. It is shown in this case intermediate dimensions of parts are counted.