Torque isn't the only part of the equation either. That point of the torque is to create enough friction so the prop doesn't slip. It really doesn't take a lot to do that if you're tightening against the drive washer with those grooves in it, or against a metal backplate made the same way. But if the surface is smooth or plastic, a piece of the open mesh sand cloth makes a decent substitute for the grooved metal surface. Villa is 100% right about using the factory supplied washer too. The farther out on the prop hub the torque is applied the more effective it is at holding the prop on.