They just lacquer the first 6 to 8 inches, the rest is all wood. So, 3000 grit SP is not gonna harm anything and will keep it smooth. I've had my OB's for a over 6 months, and for whatever reason, they seem to need a lot less cleaning ?? I don't get it, but I clean them less than my old shafts using a shaft cleaner and occasionally using 3000 grit to polish it up nice and slick