Well, a K-Drill and the Lite Flight can both be used with a cordless drill at the RPMs of the drill. I dont know the torque specs of the 40V power head, I assume the K-Drill takes a bit more torque since it has chipper blades. I would say its work trying the K-Drill on the 40V power head, I expect you would find out fairly quickly how it would work, if it cuts good I would say you are good to go, if the 40V struggles, then I wouldnt continue with it