Below is a list of Spur Gears manufacturers from San Carlos, California. A spur gear is a cylindrical or disk-shaped tool used to transfer torque to or from other industrial gears. They are among the simplest gear constructions in terms of design and operating principles. They are constructed of a cylinder or disk with simple machined teeth around its perimeter. Variable qualities of material composition, thickness and other features distinguish spur gears from each other, but their conceptual simplicity distinguishes them from all other gear varieties.