1. Self-tightening drill chuck type does not need to use the wrench to tighten, RJ mount after hand tighten the drill chuck coat, tightening force increases with the increase of the cutting force.
2. The drill chuck cannot be used in machine tools to reverse, reverse without losing the self-tightening effect.
3. The device should be taper hole when drill chuck with machine (or electric drill) clean the taper shank, aim the pyramidal taper shank centre, by hand or wooden hammer drill devices for end face, and to set up for to