Abstract: Tools for expanding (i.e., flaring and swedging) the ends of metal tubes are configured for attachment to a powered impact hammer, such as an air hammer. A swedging tool for swedging an end of a metal tube has a swedging body with a die section for expanding the tube when driven thereinto and a flanged shank attached to the swedging body and configured for engagement by a powered impact hammer. A flaring tool for flaring an end of a metal tube includes a flaring body having a die section for flaring the tube when driven thereinto. A flanged shank is attached to the flaring body and configured for engagement by a powered impact hammer. A method for expanding an end of a metal tube entails attaching a die body for expanding the end of the metal tube to a powered impact hammer, aligning the die body with the inner diameter of the metal tube, activating the powered impact hammer, and urging the die body a determined distance into the metal tube.