Woodruff Keys

Woodruff semicircular keys

These semicircular keys when set in place leave a flat end protruding. The keyway is a semi-circular pocket set into the shaft. These pockets can be set by a cutter to set the dimensions. Woodruff Keys are used to improve the concentricity of the shaft for high-speed operation. The main advantage is eliminating making a keyway near areas that have stress. The materials of Woodruff keys like keysteel and stainless steel can be ordered online but they can be found made of other materials such as Aluminum.

What is a woodruff key?

In 1888 W.N. Woodruff developed and invented the Woodruff key to mate parts to rotating shafts. He came up with the idea so that a portion of the key protrudes.  The key then prevents the part slipped over the shaft from freely rotating. Common uses are for machine tools, snowblowers, lawnmowers, Chainsaws, and propellers etc.Most motor

Most motor manufacturers such as Honda use Woodruff keys.

This design eliminates the need for expensive milling to integrate a tab into the shaft. The design also helps to keep alignment with the shaft and attached part to reduce vibration and wear at high speeds. 

Also know as Crank keys, Crankshaft keys, Harmonic damper key, key damper retainer or harmonic balancer retainer key?

The Woodruff Key is also called a crank key, crankshaft key, harmonic damper key, key damper retainer or harmonic balancer retainer key mostly due to its use.  These keys come in many of sizes be it metric or imperial profiles.

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