Vibration damped rivet bucking tool

A vibration damped rivet bucking tool comprising a housing (11) subjectable to a manual bucking force, a cylinder bore (12) in said housing, abutment means (20) at one end of said cylinder bore, a piston (13) sealingly and reciprocally disposed in said cylinder bore and defining a damping chamber (42) at the other end thereof, a rivet bucking die (23) connected to said piston (13) at said one end of said cylinder bore to form an assembly with said piston and applicable by said manual force against a rivet to be bucked, and passage means (39) for supplying compressed air to said damping chamber to cooperate with said piston for transmitting said manual force thereto and to said die during rivet bucking, characterized by said damping chamber (42) of said cylinder bore (12) having a volume exceeding the displacement volume of said piston (13) under recoil during rivet bucking sufficiently to isolate said housing (11) from undesirable vibration, and pressure reduction valve means (28) on said housing (11) connected to said passage means (39) for selectively adjusting the air pressure in said damping chamber (42) so as to bias said piston and die assembly (13, 23) onto said abutment means (20) by an elastic force approximately equal to the optimal manual force required for proper rivet heading and bucking in the riveting work at hand.