A woodruff key is a "small" part located in a keyway of a shaft or hub. There are two types: the flat key and the conical or taper key.
With the flat key, the key fits exactly into the shaft groove.
In a taper key assembly, a wedge-shaped key applies a permanent preload force. The key is also known as a half-moon key.
In our Volkswagens, the conical key is mainly used to secure the crankshaft and alternator or dynamo pulley, and to secure the fan on Type 1 and Type 3 engines. They are also used to secure the camshaft sprocket to the crankshaft and, on diesel engines, to secure the timing belt pulley to the countershaft. The specifications of the part indicate what it is used for.
The key must not be damaged or worn, and must be replaced if it is.
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