Machine spindle dynamic characteristics are precisely related to the operation and stability of the machining process. The finite element analysis (FEA) has been used to find out the dynamic behavior of spindle-bearing system. The unbalance response of the vertical machining center (VMC) spindle system at the cutting tool due to thrust force is calculated to study the dynamic properties. In this paper, Ansys Workbench rotordynamic and harmonic response have been used to make the dynamic investigation of VMC spindle and estimate the final values. Results show that the obtained critical speeds are nowhere near to the spindle operating speed range; hence, the resonance would not occur, and at operating speed, the maximum unbalance response is within an acceptable limit. The effect of rotordynamic and harmonic response on same VMC spindle system supported by hybrid bearing set is analyzed in Part 2 as an extension of this work.