[Problem to be Solved] A thread-rolling flat die for a threaded fastener capable of long life and a thread-rolling method using the thread-rolling flat die for a threaded fastener are provided.

[Means for Solving the Problem] A thread-rolling flat die 1 is provided with a first partial bite surface 15 having an inclination with an angle with respect to a finishing surface 13, and a second partial bite surface 16 formed between the first partial bite surface 15 and the finishing surface 13 and having an inclination with an angle with respect to the finishing surface 13. A crest angle 1 of a processing tooth 31 at a thread-rolling starting point 17 in the first partial bite surface 15 is larger than a crest angle 2 of a processing tooth 31 in the finishing surface 13. Therefore, loads applied to dies 10, 50 can be reduced, and this allows a longer life of the thread-rolling flat die 1.

A rolled thread screw includes: a screw part having, on an outer circumferential part of the screw part, thread crests and thread grooves disposed alternately along an axial direction of the rolled thread screw; and a columnar part adjoining at least one of both sides of the screw part in the axial direction. An axial end surface of the columnar part is provided with: a first concave surface concave in the axial direction; a second concave surface positioned to an outer circumference of the first concave surface and being concave in the axial direction; and a salient part positioned on a boundary between the first concave surface and the second concave surface and projecting further than a bottom of the first concave surface and a bottom of the second concave surface, the salient part extending in an arc-like shape along a circumferential direction of the columnar part as viewed in the axial direction.

A self-tapping screw includes a head and a shank extending from the head. The shank includes a cylindrical shank immediately below the head and a truncated conical shank following an end of the cylindrical shank. The cylindrical shank is provided with a plurality of first external threads, the truncated conical shank is provided with a plurality of second external threads following the first external threads, and a peak of each of the second external threads is provided with a biting surface having a concave-convex form.

In combination, a manway cover and a manway flange having one or more bolt opening(s) and a pull-up bolt assembly adapted to be used for supporting a hinge component to the manway cover, the manway flange, or both, where the pull-up bolt assembly having a pull-up bolt member, a nut component, a tapered member, and an expandable friction member, where one or more structures selected from a thread, a ridge and/or a groove disposed on an outside surface of the expandable friction member and the one or more bolt opening(s) having an inside surface adapted for mating with the corresponding one or more structures of the expandable friction member whereby, when the pull-up bolt assembly is engaged within the one or more bolt opening(s), the one or more structures aligns with the corresponding inside surface of the one or more bolt opening(s).

In combination, a manway cover and a manway flange having one or more bolt opening(s) and a pull-up bolt assembly adapted to be used for supporting a hinge component to the manway cover, the manway flange, or both, where the pull-up bolt assembly having a pull-up bolt member, a nut component, a tapered member, and an expandable friction member, where one or more structures selected from a thread, a ridge and/or a groove disposed on an outside surface of the expandable friction member and the one or more bolt opening(s) having an inside surface adapted for mating with the corresponding one or more structures of the expandable friction member whereby, when the pull-up bolt assembly is engaged within the one or more bolt opening(s), the one or more structures aligns with the corresponding inside surface of the one or more bolt opening(s).

Cold-forming equipment configured as a high precision thread rolling assembly utilizing racks, guide rails, a bearing assembly including rolling element linear motion bearings and a gear reduction assembly.

Cold-forming equipment configured as a high precision thread rolling assembly utilizing racks, guide rails, a bearing assembly including rolling element linear motion bearings and a gear reduction assembly.

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 screw anchor and method of forming such a screw anchor, the method comprising: forming a first male screw thread section on a metallic body and which is integral to the metallic body; and using a metal deposition technique to deposit a second male screw thread section on the metallic body; wherein the second male screw thread section is formed of metallic material having a greater hardness than the metallic body and is able to tap out a female thread in a hole in a support for receiving the first male screw thread section when the screw anchor is twisted into the hole.