A system for robotic surgery makes use of an end-effector which has been configured so that a drill connected thereto is guided in its trajectory and limited in its advancement into an associated anatomical feature by a drill guide. The drill guide may be adjusted manually to engage a corresponding surface of the drill after its advancement by a pre-selected amount. The drill guide likewise includes features to guide the drill during trajectories having oblique angles relative to the surface of the anatomical feature associated with the medical procedure.