Abstract: A percussive air tool with a hollow cylindrical stepped housing having air inlet and air exhaust ports. A stepped hammer reciprocates inside the housing and has an axial central bore with a tube element disposed in the bore. The tool includes, work stroke and return stroke chambers, an air supply hose pipe with an air feeding valve, and a rod-clamping device arranged in the forward portion of the housing. The smaller step of the hammer has a neck portion or groove adapted to communicate the air inlet port with the interior of the larger step of the housing, an open annular cavity being formed between the tube element and the walls of the hammer bore.