The present invention relates generally to a container that may be sealed and reclosed with a threaded closure. More specifically, the present invention relates to methods of manufacturing a metallic container having an opening with inwardly facing threads that are formed after a threaded closure is inserted at least partially into the opening. The container opening may be selectively sealed and reclosed with the threaded closure which releasably engages the container threads.

A method of machining a screw is provided that is capable of preventing formation of a protruding section at a thread tip section. A thread is formed by cutting on a cylindrical body, and a surface of the thread is plastically deformed by rolling. Because of the cutting, a width between-side surfaces of a thread tip section is in a narrowed state as compared to a normal width. This width is narrowed toward a tip of the thread while a thread body section has a width expanded as compared to a normal width. Consequently, the side surfaces are formed to bulge by an excess thickness portion as compared to normal side surfaces. The rolling plastically deforms both side surfaces to cause the excess thickness portion to plastically flow toward the side surfaces.

A method of machining a screw is provided that is capable of preventing formation of a protruding section at a thread tip section. A thread is formed by cutting on a cylindrical body, and a surface of the thread is plastically deformed by rolling. Because of the cutting, a width between-side surfaces of a thread tip section is in a narrowed state as compared to a normal width. This width is narrowed toward a tip of the thread while a thread body section has a width expanded as compared to a normal width. Consequently, the side surfaces are formed to bulge by an excess thickness portion as compared to normal side surfaces. The rolling plastically deforms both side surfaces to cause the excess thickness portion to plastically flow toward the side surfaces.

A hollow screw and related process of making is provided, wherein the hollow screw is formed from a generally circular corrosion resistant stainless steel disk cut from flat roll stock. The hollow screw includes a head and an elongated and hollow shaft having a wall thickness between about 0.2 to about 0.7 millimeters extending therefrom and defining a shank portion and a threaded portion having a plurality of threads thereon with a rotational drive mechanism configured to facilitate tightening via the threads. The process involves annealing to soften the stamped hollow screw, followed by thread rolling, and then age hardening the hollow screw. As such, the resultant hollow screw is relatively lightweight, about 50% the mass of a solid core screw made from the same material, with a sufficient thread strength to meet most aerospace applications and contributes to important aircraft fuel economy.

A hollow screw and related process of making is provided, wherein the hollow screw is formed from a generally circular corrosion resistant stainless steel disk cut from flat roll stock. The hollow screw includes a head and an elongated and hollow shaft having a wall thickness between about 0.2 to about 0.7 millimeters extending therefrom and defining a shank portion and a threaded portion having a plurality of threads thereon with a rotational drive mechanism configured to facilitate tightening via the threads. The process involves annealing to soften the stamped hollow screw, followed by thread rolling, and then age hardening the hollow screw. As such, the resultant hollow screw is relatively lightweight, about 50% the mass of a solid core screw made from the same material, with a sufficient thread strength to meet most aerospace applications and contributes to important aircraft fuel economy.

A bolt includes a head portion and a shaft portion. The shaft portion includes an ordinary screw portion that meshes with a nut, and a guide screw portion that is provided on a distal end side of the ordinary screw portion and has a screw thread having a diameter smaller than that of a screw thread of the ordinary screw portion. A protective portion having a diameter larger than a minor diameter of the ordinary screw portion is formed continuously from the guide screw portion at a distal end of the guide screw portion. A pressure flank surface is formed at a distal end of the screw thread of the guide screw portion, but a clearance flank surface is not formed thereat.

A bolt includes a head portion and a shaft portion. The shaft portion includes an ordinary screw portion that meshes with a nut, and a guide screw portion that is provided on a distal end side of the ordinary screw portion and has a screw thread having a diameter smaller than that of a screw thread of the ordinary screw portion. A protective portion having a diameter larger than a minor diameter of the ordinary screw portion is formed continuously from the guide screw portion at a distal end of the guide screw portion. A pressure flank surface is formed at a distal end of the screw thread of the guide screw portion, but a clearance flank surface is not formed thereat.

A form-rolling die structure with die members which are pressed against a material to be threaded and which have rigid surfaces that are relatively displaced. The die members are equipped with a plurality of independent concave portions which form a substantially parallelogram shape when viewed from the normal of a virtual surface obtained by connecting the outermost portions of each of the rigid surfaces, and which are recessed from the virtual surface. Two of the corners at the sites corresponding to the four corners of the substantially parallelogram-shape of the concave portions are rounded. The periphery of each concave portion in the cross-section along the direction of the normal is rounded along the periphery of the substantially parallelogram shape. The concave portions form a substantially truncated-pyramid shape.

A form-rolling die structure with die members which are pressed against a material to be threaded and which have rigid surfaces that are relatively displaced. The die members are equipped with a plurality of independent concave portions which form a substantially parallelogram shape when viewed from the normal of a virtual surface obtained by connecting the outermost portions of each of the rigid surfaces, and which are recessed from the virtual surface. Two of the corners at the sites corresponding to the four corners of the substantially parallelogram-shape of the concave portions are rounded. The periphery of each concave portion in the cross-section along the direction of the normal is rounded along the periphery of the substantially parallelogram shape. The concave portions form a substantially truncated-pyramid shape.

A thread-rolling flat die for a threaded fastener, includes a thread-rolling surface including at least a bite surface to which a workpiece of the threaded fastener is supplied, a finishing surface formed adjacent to the bite surface, and a roll-off surface formed adjacent to the finishing surface. The bite surface includes at least: a first partial bite surface having an inclination and a second partial bite surface formed continuously from the first partial bite surface and having an inclination. A length L1 along a thread-rolling direction in the first partial bite surface, a length L3 along the thread-rolling direction in the finishing surface, a length L4 along the thread-rolling direction in the roll-off surface, and a diameter of a processed portion of the workpiece of the threaded fastener have a relationship of L1>L3>L4> the diameter of the processed portion.