An end effector of a surgical tool includes a first jaw and a second jaw rotated by a driving pulley. A first driven pulley is attached to the first jaw and a second driven pulley is attached to the second jaw. A first end portion of a first cable is connected to a first radial side of the first driven pulley, a second end portion of the first cable is connected to a second radial side of the second driven pulley, and an intermediate portion of the first cable is connected to the driving pulley. A first end portion of a second cable is connected to a first radial side of the second driven pulley, a second end portion of the second cable is connected to a second radial side of the first driven pulley, and an intermediate portion of the second cable is connected to the driving pulley.