A tool condition monitoring system will reduce machine downtime, eliminate tool/workpiece destruction, and maximize tool life. Several of the cutting tool failure modes are cutting temperature-dependent. One of the cutting parameters to be monitored is the cutting temperature. On-line cutting tool temperature monitoring has been addressed with a variety of techniques, from work-tool thermocouples to embedded thermocouples to infrared radiation technology. However, these methods are not durable and robust enough to provide quick, accurate results from a production environment. The objective of this research work was, therefore to investigate the applicability of a thin film Platinum Resistance Temperature Detector (PRTD) sensor in the monitoring of cutting tool temperature for a turning tool. The thin film PRTD offers a small size, industrially durable method of monitoring cutting tool temperature with a quick response time. The sensor is placed under the cutting tool insert near the tool nose and is spring-loaded to ensure intimate contact. The sensor's output was correlated to those of a thermocouple, located at the nose of the insert and compared to estimated cutting temperatures using existing empirical models. Both sensor's were calibrated using a torch as an infinite heat source. Experimental results obtained under different cutting conditions indicate a high potential for the use of the thin film PRTD sensor for on-line cutting temperature monitoring in an industrial setting. / Master of Science