Keys and Keyways
A key is a common machine element found in rotating equipment used to connect a rotating component to a shaft. The key prevents movement and relative rotation between the component and the shaft and may also enable torque transmission. To function properly, the shaft and rotating component must have a keyway and a keyseat, which is a groove and pocket where the key is fitted. Keyways are cut vertically or horizontally along the surface of a shaft and the type of key and keyway that is milled depends on what type of work it is intended for. Keyways are commonly used in gears, impellers, stub shafts, couplings, pump sleeves, or any part that requires an internal keyway or slot for connection. Though keyways are often cut on key seating machines; they can also be cut using wire-cut EDM, shaping, and milling.
Keyway milling, when performed, is able to cut partial length, straight or tapered keyways into a shaft. This method is commonly used to mill external shaft keyways. When milling with an end mill, a hole with the same diameter as the milling cutter is drilled at one end of the groove bottom, and the depth is the same groove depth.