This sector gear is specially manufactured with special molding processes. A sector gear is a flat spur type device that only has teeth along a short section of its circumference; the remaining portion of the gear is smooth. These gears are used to drive other elements or are driven themselves in mechanisms which only travel through a short arc and not a complete revolution. They are typically found in mechanisms which feature short, repetitive, or reciprocating movements such as clocks, actuators, and steering units.