On many of Anvil's drive shafts we use feather keys to transmit power. Keys and keyways are suitable for any shaft joint that transmits rotational forces. If the shaft has to move in a linear stroke too, splines should be used.
| Creating an external keyway on a shaft is simple if you have access to a milling machine, A suitably sized slot drill will produce the form required to fit the key. |
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Internal keyways in through holes can be produced using a broach or careful filing. However, a keyway in a blind hole (a hole with a bottom) usually requires the use of a slotting head. We had three keyed shafts that required internal keyways in blind holes, and as we had no slotting head we devised this solution: |
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| 1. Produce the shaft as normal, drill and ream the hole for the input shaft, turn down the end to be keyed to the radius of the input shaft plus the height that the key will project. It helps to leave a shoulder behind the key area. At the same time make up a sleeve that fits closely to the diameter of the turned section. |
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| 2. Using a slot drill, cut out the key slot from the turned section. Ensure the shaft and key will sit at the correct depth into the hole. |
 
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| 3. Slide the sleeve onto the shaft to complete the keyway, the sleeve prevents spreading of the key slot and as long as it is supported at both ends you should have no problems. The shoulder supports one end, the other is up to you. You could run a fine weld around the groove, but beware of distortion. |
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