In this article we report on part of our research in piano action models, hoping to convey the need for research on this topic by explaining the shortcomings of most synthesizer keyboard-scan techniques. We have developed a new piano-key action model, based on a detailed description of a grand piano action. Every component plays a role in the specific behavior of the mechanism. Our model's accuracy is illustrated with several simulations, To use this mathematical description in a digital piano, we are now working on a reduced model. The first result of this reduction, which also can be used for real-time applications, is shown.