A STORED PROGRAM COMPUTER USES INPUT NUMERICAL INFORMATION TO CONTROL THE PATH OF MOTION OF A LATHE CUTTER RELATIVE TO THE LATHE SPINDLE. THE SYSTEM ALSO CONTROLS THE RATE OF MOTION OF THE CUTTER ALONG ITS PATH AND THE RATE OF ROTATION OF THE SPINDLE IN SUCH A WAY AS TO ATTAIN A PREDETERMINED USEFUL CUTTER LIFE AND A MAXIMUM VOLUME OF METAL REMOVAL BY THE CUTTER DURING THAT LIFE. THE FORCE EXERTED BY THE CUTTER ON THE WORKPIECE IS MEASURED BY A TRANSDUCER TO PRODUCE A SIGNAL WHICH IS OPERATED UPON IN CONNECTION WITH INFORMATION ON THE TAPE TO PRODUCE AN INCHES-PER-REVOLUTION NUMBER. THIS NUMBER IS MULTIPLIED BY A NUMBER DERIVED FROM A SPINDLE SPEED TRANSDUCER TO DEVELOP A FEEDRATE NUMBER TO CONTROL THE RATE OF OPERATION OF INTERPOLATORS WHICH GENERATE CONTROL SIGNALS FOR THE TWO MUTUALLY PERPENDICULAR CUTTER

DRIVE AXES. THE INCHES-PER-REVOLUTION NUMBER IS ALSO OPERATED UPON BY INFORMATION OBTAINED FROM THE TAPE AND A NUMBER PROPORTIONAL TO THE NORMAL DISTANCE BETWEEN THE CUTTER AND THE SPINDLE AXIS TO DEVELOP A DRIVE SIGNAL FOR THE SPINDLE.