Apologies Ken for putting Mark's name at the top of my post to you. I probably had my question in mind about the curved lathe tools when I did that.

Mark.
Thanks for the vid. I wasn't envisioning the tool for rotating the round blades on the wheels. Although my old sharpening Yoda would probably have gasped at the jagged edge and uneven bevel it showed as a result in the video. However, you are no doubt correct. You probably just do not need the level of precision on a lathe tool that he would have aspired to.

With great power comes Awesome irresponsibility.