Why can an electric drill pinch the drill so tightly?
Because of the three teeth that had bitten the drill, there was a fixed steel ring. Ah, the three teeth were cone-shaped, and they rolled down, so they snapped
There are three teeth scattered drill chuck, the teeth are retractable, with different thickness of the drill bit used to hold, in the roots of teeth (in the rotating disc, invisible), a spin silk, when rotating clockwise, wire like screw the teeth out, caught the drill bit, otherwise return to loosen the drill bit.
There are three teeth drill chuck for clamping with dispersed telescopic drill root thickness (spin disc saw on the spin silk) when rotating clockwise when the wire with the screw like his teeth out and returned to loosen the clamp drill bit
