I have just about finished building one and need to know about the
action it should have. I read on a web site for commercial polishers
that they use 3600 rpm as the speed, so I set it for that. But I don't
know how vigorous it should be. Does one of these *just* vibrate, or is
there a noticeable shaking to the action? Putting it quantitatively,
how much displacement (side to side) does a v-p have?

Thanks,
Bob