A crimping tool for a rivet nut or an earth bond, comprising: a housing (34) adapted to receive an electrical battery; an electrical motor (101); a support (109,130) for supporting movement of a traction rod (121) in relation to the housing; a first mechanical drive train (104,105,106,106a,1071) drivable by the motor to cause rotation of a traction rod (121) about a longitudinal axis X-X in a screwing direction or an unscrewing direction; a second drive train (102,103,108,109,110,111,111a,111b,112,113,116,118,140) comprising a hydraulic pump (111,111a,111b,112,118) fluidly coupled to a piston chamber (140) containing a traction piston (113) wherein the traction piston is movable from an initial position in the piston chamber by way of fluid pressure from the pump to cause axial displacement of a traction rod towards the housing and wherein the pump of the second drive train is drivable by the motor to deliver fluid pressure to the piston chamber.