An apparatus comprises a body assembly a shaft assembly an end effector an articulation section and an articulation control assembly. The end effector is located at a distal end of the shaft assembly and comprises an ultrasonic blade. The articulation section is coupled with the shaft assembly and is operable to articulate to thereby deflect the end effector from the longitudinal axis. The articulation control assembly comprises first and second threaded members and an articulation control. The first and second threaded members have respective first and second pitch orientations. The articulation control is rotatable to thereby drive articulation of the articulation section by causing translation of the first and second threaded members along a path that is parallel to the longitudinal axis of the shaft assembly. The axis of rotation of the articulation control is non parallel with the longitudinal axis of the shaft assembly.
