10039 APU integrated self-tightening drill chuck handle BT30/BT40/BT50-APU08/13/16 drill toolholderBT30 BT40 BT50 APU08 13 16 drill toolholder 1. Rotary automatic clamping is fast and efficient Increased torque during machining increases the clamping force. 2. Unique, high speed and stable measurement tools imported from Germany are used to detect the measured runout accuracy of the dynamically balanced shank <0. 005mm. 3. Hardened and hardened, high hardness and durability. 4. Arc transition chamfering process