Woodruff keys, also known as "half-moon" keys due to their rounded shape, are often used on tapered shafts or near shaft shoulders, where a standard square key would create too much stress on the shaft. They are used to connect gears and many other components to shafts and work well in components that require frequent maintenance as they are easier to remove than straight square keys. Woodruff keys can sustain a great amount of stress and it is impossible for them to roll over when they are in place. Made from unplated alloy steel for strength and resistance to wear.