Apparatus for controlling cutting machines

A cutting machine, comprising:

• a cutting tool for cutting a workpiece;
• a plurality of switches, each switch corresponding to a predetermined cutting speed for each of various groups of materials having different machinability qualities;
• and
• a plurality of constant voltage output means, one of each of said constant voltage output means being connected with one of each of said plurality of switches for changing the speed of the cutting tool responsive to said constant voltage output means, said means including a pulley having two pulley halves that can be adjust to create varying pulley diameters.
• means for detecting the setting of the speed changing means;
• means for comparing a selected preferred cutting speed with the detected setting of the speed changing means;
• means for driving the speed changing means in response to the comparing means to set the speed changing means to the selected preferred cutting speed.