Wood has a 1x handle modifier meaning it doesn't decrease or increase the head durability. Stone has a less than 1x multiplier. I think 0.7, can't look now. That means you get only 70%of the head durability. Handle modifiers mean a lot. Look in the red book for info non each materialJust a question, but why do wooden tool rods give better durability when combined with stone? Surely stone is better.