A surgical instrument including a surgical end effector and a threaded rotary input shaft. An actuator member is in operable engagement with the surgical end effector and is in selective threaded engagement with the threaded rotary input shaft such that when the actuator member is in an engaged configuration, rotation of said threaded rotary input shaft causes the actuator member to move axially to impart an actuation motion to the surgical end effector and when the actuator member is in a disengaged configuration, rotation of the threaded rotary input shaft will not be imparted to the actuator member. A switch may be employed for selectively moving the actuator between the engaged and disengaged configurations. A locking system may be employed for preventing axial movement of the actuator member when the actuator member is in the disengaged configuration.