Nice work, Homemade knobs do add a nice touch to projects.

As has already been mentioned the sharp edges on knobs like that can be a problem. I've found that one of the better ways to smooth out the edges is to use scotch bright wheels in a die grinder at the lathe. I've never gone full polish though.

The nice thing about DIY knobs is that you can add any feature you might need that can't be easily had with the pre made stuff.