For use in diverse belt-tensioning systems Messrs. Dömer manufactures large quantities of so-called pulley halves. When assembled these serve to guide the belt in the motor and must satisfy roundness requirements in the area of 2 to 3 hundredths millimetres for the internal bearing seat. In addition the geometry specified for the external surface must be maintained exactly in order to ensure smooth running of the belt. The combination of press and dies as specially matched to this deep-drawing process ensure high process stability in the production of these deep-drawn parts.