The Tool Material Couple application allows optimal cutting conditions to be set. These conditions determine the cutting speeds for maximum tool life and act as criteria to help solve tool wear problems by determining the point at which tools are no longer safe to operate. Measures of the cutting forces explain the behavior of the components during machining, and show an interesting evolution of the angle between the result component of the main cutting force Fc and the component of the tangential force Fy. This angle remained constant during 3000 m of machined MDF with a low chip thickness. It is possible to determine the effective machining time, the moment of the increased cutting force, and its angular variation. This can also be useful in determining the maximal length of cut for a specific tool, with conditions of correct surface roughness. The evolution of these changes can be followed and the value of both components of the cutting force determined precisely. The normal component of the cutting force is a critical factor in the angle variation.