Optimizing the profit of an individual cutting tool is crucial to the computer numerically controlled (CNC) machining industry. In this paper, the mathematical modeling, the dynamic solution, and the decision criteria through calculus of variations are introduced to achieve the optimal material removal rate (MRR) control of a cutting tool under the fixed tool life. To realize the optimum MRR, a commercialized lathe system with a digital processor controller (DSP) and a man-machine interface is developed. Additionally, the implementation of dynamic MRR control for a real-world industrial case is experimentally performed on our proposed digital PC-based lathe system. It is found that the surface roughness (R a ) of all machined work-pieces not only stabilizes as the tool consumed, but also accomplishes the recognized standard for finish turning. In this study, the adaptability of the dynamic control of optimum MRR as well as the realization of the digital PC-based lathe system are absolutely guaranteed.