Abstract: An apparatus and method for tool condition and failure monitoring system for predicting imminent tool failure by sensing acoustic emissions from a cutting operation converting the emissions into an electrical signal filtering the electrical signal and using a "count rate" technique on the filtered signal to generate a signal indicative of imminent failure. To improve the prediction, the filtering includes removal of low frequency and d.c. signals and the imminent failure is indicated only after several successive periods of a triggering level of count rate.