A LASER LINE RANGING SYSTEM HAS BEEN DEVELOPED FOR 3-D ON-MACHINE DIGITIZING OF PRECISION PART FEATURES REQUIRING FINISH PROCESSING. THE SYSTEM CONSISTS OF A LASER LINE PROJECTOR AND CCD CAMERA, A SET OF SPECIALIZED ON-MACHINE CALIBRATION ROUTINES, A SPECIALLY DESIGNED CALIBRATION TARGET AND A SET OF SURFACE SPLINE FITTING ROUTINES THAT TAKE, AS INPUT, THE LASER LINE GENERATED 3-D PART DATA. THIS ON-MACHINE GAGING SYSTEM IS APPLICABLE TO A NUMBER OF IMPORTANT MACHINING TASKS FOR WHICH THE POSITION OF THE PART FEATURE TO BE PROCESSED IS NOT WELL-ENOUGH DEFINED FROM CONVENTIONAL PROGRAMMING TECHNIQUES. IN THESE MACHINING TASKS, ON-MACHINE GAGING IS REQUIRED TO PROBE THE PART FEATURE AND ACCURATELY LOCATE IT IN SPACE. THE CURRENT WORK FOCUSED ON PLASMA SPRAYED TURBINE BLADE CASTINGS WHICH REQUIRE OVERSPRAY REMOVAL TO TOLERANCES FAR STRICTER THAN THE DEGREE TO WHICH THE CASTING CAN BE LOCAT