[AT] key-ways

[Greg Hass]

I'm working on an "invention" for my roll-over plow. More when I have 
time. It will have 2 shafts with a sprocket in the middle and rubber 
blades on each end (similar to the straw spreader on combines) . I will 
need 3 keys on each shaft; each shaft is about 20 inches long. My 
question is; should I use straight keys or half moon keys. They will be 
powered by a hydraulic motor that ran the reel on a IH 715 combine.
       Greg Hass