In this paper, the superposition method was used to obtain the solution for the forced vibration of clamped-free-clamped-free (CFCF) isotropic rectangular plates subjected to a concentrated drilling force. This method was found to work extremely well, and fewer terms in the series were used to provide an equivalent accuracy of solutions. The drilling force signals can be represented by Fourier series; the terms of the series were used to calculate the plate dynamic response at any point on the plate surface. The effect of the drilling conditions on Fourier series terms was analyzed and an empirical equation was derived to calculate the fundamental Fourier frequency at different drilling conditions. It was found that the speed and feed have pronounced effects on the Fourier fundamental frequency term.