Woodruff Keys

Woodruff keys - Metric Kit

Woodruff keys are semicircular, such that, when installed, they leave a protruding flat end. The keyway in the shaft is a semi-circular pocket; the mating part is a longitudinal slot. They are used to improve the concentricity of the shaft and the mating part, which is critical for high speed operation. The main advantage of the Woodruff key is that it eliminates milling a keyway near shaft shoulders, which already have stress concentrations.

This type of key was developed by W.N. Woodruff of Connecticut. In 1888, he was awarded the John Scott Medal by the Franklin Institute for his inventio

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  A Woodruff key installed

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  A Woodruff key and keyway

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  Gear G is positively located on shaft S by Woodruff key N