ummm... off the top of my head i dont recall... google for 'specific cutting power'... its 17 for aluminium... that allows you to work out for a given material removal rate how much power is needed and therefore also, given revs the torque, which given a cutter size, gives the force applied and thats a guesstimate for the cutting force at the cutter... its rough and ready so we've generally doubled it... some hardwoods are nearly as tough as ali!