Impact manipulation instantaneously generates a large force making it effective for pressfitting. We model pressfitting and analyze it for realization by a robot manipulator, analyzing the relationship between hit speed and pressfitting depth to determine the hit speed required for different pressfitting depths. We use an under-actuated manipulator for hitting the “sweet spot” of the end effector, introducing a simple genetic algorithm to plan manipulator movement to generate the desired hit speed. Results of experiments on pressfitting for driving an under-actuated manipulator verified the feasibility of our proposal.