Spur gearing was the first type of gear to be developed. They are still widely used in industry, offering uniform ratio and positive shaft locations. They are cylindrical in form and operate on parallel axes. Advantages of spur gears are ease of assembly, minimum maintenance, and high strength and efficiency. They are priced economically because the straight tooth form is easy to manufacture. This tooth design also eliminates end thrust or side movement found in helical gearing. Spur gears are usually found on slow or medium speed machinery. This is due to the minimum number of teeth in contact at the same time between the pinion and driven gear.