A flaring tool is provided for flaring an end of a pipe or tube. The tool includes a locking mechanism having a collar and a collet with two or more collet pieces that engage the collar prior to and during a flaring operation. The collet can receive a pipe or tube when the collet is in an expanded or open position. The collet pieces have external flanges for engaging the collar during clamping and unclamping of the tube, each flange having first and second flange portions that sequentially engage an inner surface of the collar, the first flange portion guiding insertion of the collet into the collar and the second flange portion causing the collet pieces to clamp onto the tube. A flaring mechanism moves a flaring mandrel towards the end of the tube when the collet is clamped, whereby the mandrel engages and flares the end of the tube.