Originally Posted by ronrandle
My question was really aimed at determining why a motor that can only be mounted in one direction, would use a collet, rather than an integrated prop mount.
I have wondered the same thing from time to time. Some of the larger Scorpion and Hacker motors have a built in threaded prop shaft and prop washer. This would be the best of both worlds, as long as the threading doesn't become the weak point. There were many early engines that had machined bolts fail at the start of the threads along the shank. They were machining the threads and causing a stress point where they started near the head. They started rolling the threads into the metal and those stresses went away. (Thanks "How It's Made".
) That being said, I can't remember having problems with collets not holding onto the shaft. I usually have problems getting them off the shaft after a while.
Thanks Hyperion for the Collet Pullers.