IMHO, there is nothing I do that makes the risk using a bench mounted buffer worth the risk. After reading all the warnings on here and taking all the precautions I could, I still had a blade thrown at me and almost castrated myself. After that, I bought a 7" variable speed (0 - 2500 rpm) buffer and some good lambs wool wheels. I clamp the blade or handle, depending on what I am buffing, in a vice and go at it. I can mirror polish a blade or bring a handle to a 6' deep shine. It probably takes a little longer than a bench mtd. buffer but it is a hell of a lot safer.
Tim
As a beginning knife maker I've been on the fence about spending the money on an expensive buffer. The option you've presented seems to be a much safer, less expensive alternative. I'd love to hear more about how you use this setup... how to apply compounds, technique, etc.