the working piston 14 to be moved towards the left in fig1 in addition the air from the passage 104 in the body portion 100 flows towards the left in fig1 to a recess or opening 105 in the housing 101 and from there into a suction chamber 106 and then by way of bores 107 into the interior of the piston rod 108 which is connected to the working piston 14 there the air serves for sucking the rivet unless depending on the design configuration of the tool the operation to be performed is that of screwing on a screwthreaded rivet nut in addition the air flowing through the bores 107 in the piston rod 108 is available for removing the rivet pins rearwardly through the passage 109 which is indicated at the right in fig1 and 2 the tool also includes an adjusting valve 110 for steplessly adjusting the strength of the air flow and thus the force produced by the air insofar as the valve 110 can be suitably adjusted by means of a cap nut 20 or an adjusting screw which is not illustrated in the drawings in addition the air flowing through the passage 201 in the valve rod 27 flows through a lower transverse passage 209 in the valve rod 27 into a pressure chamber 210 associated with a pressing piston 211 the chamber 210 being disposed above the pressing piston 211 and thus being disposed at the rear thereof in the operative direction of movement of.