In this master thesis a hammer mill was developed and designed with the possibility of installing an electric motor with a power of 5.5 to 7.5 kW. Loads were determined and calculations were made in order to check the stresses in the components of the rotor. The disc stress and displacement results obtained by analytical methods of strength of materials were verified and compared with the results of the finite element method. The existing dynamic safety factor of the shaft was checked and the bending and torsional critical speeds were estimated. For the purposes of estimation of the torsional critical speed and the starting time of the electric motor, the mass moment of inertia of the rotor was calculated and compared with that from the computer program. Stresses were kept low for safety reasons but also because of the exposure of functional parts to abrasive wear. The structure of the mill is solid and rigid. At the end, a 3D model of the hammer mill with final dimensions is presented.