Apparatus for making a drill screw with an extruded point

Claim 1

A pair of complementary die members adapted to be moved laterally toward and away from each other to define a die cavity and provide for the cold forging of the work-entering end of a blank into a drill point of a self-thread forming screw said blank having a shank portion having a first diameter, a head at one end of said shank portion, and a work-entering end portion having a second diameter smaller than said first diameter, said die members having jaws offset with respect to each other and with respect to the longitudinal centerline of said die cavity, said jaws having facing surfaces both diverging away from said longitudinal centerline in a direction away from the entering end of said cavity within which said blank is to be disposed, said jaws adapted to form a pair of flutes extending the length of said work-entering end portion on opposite sides thereof and a pair of longitudinally extending land portions between said flutes, each of said die members having a sidewall portion which closely overlaps the jaw of the other die member completely to surround the sides of said work-entering end portion of said blank when the same is placed therebetween to limited lateral expansion of said portion and preclude the formation of any lateral flashing, each of said die members having a curved wall portion connecting said jaw and said sidewall portion, said curved wall portions having the same radius of curvature as the land portion to be formed thereby, and extending substantially parallel to said longitudinal axis, the die cavity defineD by said die members having a depth greater than the length of said work-entering end portion of said blank with said diverging facing surfaces and said curved wall portions extending to the extremity of said cavity remote from said entering end, to permit unrestricted longitudinal extrusion of said end portion upon closure thereof, said curved wall portions of said die members defining segments of a circle when in their fully closed position to form said land portions with a diametrical width substantially equal to said first diameter of said shank portion, said inclined facing surfaces of said jaws providing the forward faces of said land portions with a hook at the work-entering extremities thereof.