An electromechanical surgical system (10) having an instrument housing (102) for connecting with a shaft assembly (200), a shaft assembly (200), and an end effector (400). The end effector (400) is an articulating end effector and the system includes a cable tensioning system (1320) for tensioning the articulation cables (262,264). The system includes a clutch mechanism (1360) for preventing slippage of a drive cable.