Abstract: A drill is provided on which the chuck and motor are mounted on a support which moves vertically. Thus the motor rises and falls with the movement of the drill. Also the vertical movement of the drill chuck is controlled by an air cylinder which has mounted axially above it an hydraulic checking cylinder arranged so that checking occurs after an initial unchecked downward movement of the chuck. Automatic and manual operation are controlled by a five port valve in which a piston changing the air direction flow is moved by air blasts directed to each end of the channel in which the piston moves.