puller nut and then tap one of the blades with the wooden end of a hammer it will set up a harmonic that will cause the prop to pop right off. You never need to use any king of a hammer to hit the prop. Just keep the harmonic going and it will eventually come off. I agree that a correctly fit shaft to prop connection shouldn't slip but the "key", pardon my pun, is that everything is a snug fit. I my mind, a key sliding around in the key way just isn't right. I've seen keys and key way damage so I always try to get everything all working together.