The machine allows to directly cold-impress the steel cutting edge for symbolic numbering without having to heat the material. The machine hydraulic operation results in high operating frequency. The insert-shaped tools developed by STERN deform steel considerably avoiding both breakings and a lowering in the cutting edge. Thanks to both revolving insert carriers, four pairs of inserts can be used at a time. The carriers can rotate simultaneously by operating the handwheel on the front side. With the indexed handwheel on the rear side penetration depth of tools can be varied by centesimal increments as to adapt them to the various requirements and different kinds of steel. The inserts, available in various shapes, show a very close tolerance. The use of special high quality materials and a series of heat treatments developed by STERN assure them a long life.