Nanoelectromechanical systems (NEMS) are devices integrating electrical and mechanical functionality on the nanoscale.Because of individual electron tunneling, such Boxes systems can show rich self-induced, highly nonlinear dynamics.We show theoretically that rotor shuttles, fundamental NEMS without intrinsic frequencies, are able to rectify an oscillatory bias voltage over a wide range of external parameters in a highly controlled manner, even if subject to the stochastic nature of electron tunneling and thermal noise.Supplemented by a simple analytic model, we identify different operational modes of charge rectification.Intriguingly, the Butcher direction of the current depends sensitively on the external parameters.