I tried to sharpen a plane iron on a leather wheel with the wheel rotating toward me one time. Leather flew everywhere. The plane iron bounced off the bench, to the ceiling, and left a pretty fair gash in the wall behind me. Only scratched my thumb, but it coulda been really ugly. Imagine that razor sharp plane iron as a projectile, and you'll get the picture.
But it did scare the &%$* outta me. (Harry Boyd)
Oy... I've had projectiles in the shop before, back in the days when I was manufacturing model airplane kits, and cutting wood on a table saw. That was before I invested in a band saw to do the production cutting. Even with feather boards, with the feed rates I was using I would get a piece to fly out every once in a while. Learned very quickly to stand off to the side of the work piece. Wit a planing iron launching off of a rotating wheel, I could see it would be just a tad more dangerous. Having the plane blade ricochet off nearby surfaces makes it a bit harder to stay out of the way. Danger lurks in the shop when we are the least bit inattentive. (Mark Wendt)