Hi, Mark. I’d be interested in other responses to this. From what I’ve seen, there’s no general agreement on the subject. There’s the obvious factor that higher speed should mean faster cutting, and there is the “hydroplaning” consideration at high speeds.
I have seen specific recommendations, even by lap manufacturers, and it would be interesting to know the reasoning behind them.
I use a 1640 RPM motor with a 4 step pulley. I use the smallest step for polishing, I’m guesstimating about 250 rpm. I use the next to largest step for cutting, guesstimating 850 rpm? Somewhere in my tool pile I have an optical timing light (for measuring rpm on diesel motors), as soon as I find it I will update with accurate speeds.
Still on hold for the optical timing light. Haven’t used it for several years, but it’s around here somewhere. Can’t even blame this one on the wife. She likes to move my stuff from wherever I left it to a more ideal location. She then develops amnesia when I ask where she put it.
I use speed as a complement to what I want to accomplish. Speed to me is a reason for me to do it faster, to accomplish more in less time than I want to give in time. I sweep different to to get the effect of the speed to gain efficiency in my cut to flat and meet.