A surgical end effector includes a clevis and two jaws rotatably coupled to the clevis. A rocking pin in the form of a solid of revolution is pivotally supported by the clevis. The rocking pin may be pivotally supported by the clevis at the midpoint between the first and second ends. The opposite ends of the rocking pin engage the jaws to constrain the jaws to have opposite motions around the axes of rotation of the jaws. The clevis may be coupled to an elongate shaft to provide an endoscopic instrument. The first and second jaws may electrically isolated from one another for electrocautery and the rocking pin may be formed from a non-conductive material or electrically isolated from the first and second jaws by electrically non-conductive liners. The jaws may be opened and closed by pushing and pulling on wires coupled to the jaws.
