The film shows the process of chip formation on a polished and etched specimen of C 45 W 3 unalloyed tool steel. The various phenomena of chip formation and the individual deformation processes can be observed particularly well in the perlitic-ferritic structure of the material. The rake angle affects the type and extent of the stresses and strains to which the material is subjected in that the upsetting action and hence the shear strain increase as the positive rake angle becomes smaller and eventually turns negative. From this results the change from uniform flow chips at +45 degrees to irregular shear chips (curl chips) at -20 degrees.