Abstract: An air-hydraulic blind-riveting tool has a chuck which is normally urged into a ready position by a spring and which is drawn into a retracted position by a fluid-operated piston connected via a hydraulic link to an air piston subdividing an air chamber of the tool into a front and a rear compartment. The front compartment is vented to the outside and the rear compartment is connectable via a trigger-operated valve to a source of compressed air. Thus when this rear compartment is pressurized the air piston is displaced forward and the working piston connected to the chuck is retracted. A valve is provided between the rear compartment and the atmosphere which comprises a valve disk displaceable by pressure in the rear compartment against a valve seat to prevent air from leaving the rear compartment but normally urged by a relatively stiff spring away from this valve seat.