To achieve high machining efficiency using increased table feed it is necessary to increase the number of teeth of the face mill. Fine and extra fine pitch face milling cutters have extra teeth, therefore by maintaining the same feed per tooth the table feed can be automatically be increased.
However, as the number of teeth increase so too does the cutting resistance. Therefore, when selecting fine or extra fine pitch cutters it is necessary not only to think about the cutting conditions but also to take into consideration the workpiece geometry, clamping rigidity and machine power. The reason being is that if larger depths of cut are used and / or the workpiece and clamping are insufficient, vibrations can occur and the desired high machining efficiency may not be achieved.
In general, increasing the number of teeth is very effective for machining cast iron where the cutting resistance is low.