Method and apparatus for making a threaded fastener with captive clamping means

Claim 1

A roll-thread and annular-ring die for manufaCturing externally threaded shanks having a retaining ring adjacent one extremity thereof, comprising in combination: a. a roll thread die blank having a thread-forming configuration angularly disposed on an exposed die surface thereof relative to the normal direction of travel of said die, the direction of travel of said die being generally normal to the axis of the shanks being processed therein, and a slot on an adjacent side communicating with said exposed die surface; b. a die insert in said slot and securable in fixed relationship to said die blank in a roll thread machine and having an exposed die surface substantially co-extensive with the exposed die surface of said blank, the die surface of said die insert having a face thereon with a longitudinal groove-forming surface of progressively-increasing height in a transverse shank direction and disposed to form a groove in the shank of a workpiece as it is simultaneously threaded by the die blank, said groove-forming face being located adjacent an inner portion of said insert and having an outer edge progressively extending away from the inner portion in a shank-axis direction as the groove-forming surface increases in height so that the groove-forming surface is angularly disposed relative to the normal direction of travel of said die blank and opposite to that of said thread-forming configuration, at least a portion of the adjacent outer surface of the die insert being beveled to spin the metal transferred from the shank groove into an annular ring on the shank.