A dust extraction system for a power tool having a output shaft, a collet configured for engaging a tool bit and a collet nut engageable to the output shaft, comprises a base configured for mounting on the power tool, the base defining a cavity having an opening for passage of the output shaft therethrough and a discharge chute in communication with the cavity. The system further includes an impeller sized and configured to be rotatably received within the cavity, including a hub and a plurality of vanes emanating from the hub configured to draw dust from the workpiece into the cavity and to direct the dust through the discharge chute. A collet nut is integrated into the hub of the impeller so that the impeller can be directly mounted to the output shaft of the power tool while clamping the collet onto the tool bit.