Parallel kinematic machines exhibit strong position-dependent dynamic behavior, which changes the stability and the productive cutting conditions within the machine work volume. In this paper, position-dependency of a hybrid serial-parallel scissor kinematic machine is modeled by synthesizing its substructural reduced order finite element models. The model allows the efficient investigation of position-dependency as an alternative to using time consuming full order finite element models. The predicted position dependency of the machine with the reduced order model is experimentally validated. Stability maps are simulated as a function of machine positions to identify the productivity levels within the machine work volume.