Abstract: A tool for actuating hammer unions. The tool provides for an arcuate tool head having an aperture which receives the lug or tab of the union. Extending outwardly from the arcuate tool head is a lever member which is designed to receive a handle [selected by the user for appropriate length and torque] for the user to hold and apply the necessary amount of torque to tighten or loosen the hammer union. By receiving the tab in the arcuate head, the user is precluded from damaging the tabs or lugs since no impact is received by the latter and a maximum amount of work can be done safely by the user. Structural features are also provided to prevent improper use of the tool.