Cutting discs are affected by various forces which cause stresses and deflections on the discs. Lateral deflection is one of the most frequent. It is important to know that major lateral deflections can cause undesired failures on the disc. In this study, time/frequency analysis of deflection on a cutting disc used in metal sawing process has been performed. The deflections are measured by using a laser device called KEYENCE and data recorded during the cutting process. The data sequence is converted into frequency domain with Fourier transform techniques and frequency components are analyzed. It is observed that some frequency components carry important information about the process. Using this information, the starting and ending times of cutting are determined and presented.