A threaded fastener having a prevailing torque feature and a method for forming same includes a barrel having a longitudinal axis. The barrel has a plurality of internal threads, each internal thread including a forward facing surface and a rearward facing surface. A first angle between the rearward facing surface and a first lateral axis perpendicular to the longitudinal axis ranges from 20° to 40°. A second angle between the forward facing surface and the rearward facing surface ranges from 80° to 100°.

A threaded fastener having a prevailing torque feature and a method for forming same includes a barrel having a longitudinal axis. The barrel has a plurality of internal threads, each internal thread including a forward facing surface and a rearward facing surface. A first angle between the rearward facing surface and a first lateral axis perpendicular to the longitudinal axis ranges from 20° to 40°. A second angle between the forward facing surface and the rearward facing surface ranges from 80° to 100°.

A method for setting a screw, which has an external thread in a front region and a drive in a rear region for introducing a torque into the screw, in a drilled hole in a substrate of a mineral material includes producing an internal thread in the drilled hole by a threaded drill provided with a cutting thread and then introducing the screw into the drilled hole and in so doing the external thread of the screw is screwed into the internal thread, produced by the threaded drill, in the drilled hole. The external diameter of the cutting thread of the threaded drill is smaller than the external diameter of the external thread of the screw.

A method for setting a screw, which has an external thread in a front region and a drive in a rear region for introducing a torque into the screw, in a drilled hole in a substrate of a mineral material includes producing an internal thread in the drilled hole by a threaded drill provided with a cutting thread and then introducing the screw into the drilled hole and in so doing the external thread of the screw is screwed into the internal thread, produced by the threaded drill, in the drilled hole. The external diameter of the cutting thread of the threaded drill is smaller than the external diameter of the external thread of the screw.

The present invention provides a looseness-prevention screw thread structure including a screw thread having a predetermined pitch, a no-load flank which is an inclined surface in a direction in which the screw thread is advanced, and a load flank which is an inclined surface in a direction in which the screw thread is retracted, the no-load flank and the load flank being formed at both sides of the screw thread, in which the no-load flank of the screw thread includes: a first tangential portion which abuts against an arc portion formed at a thread crest of an opposing fastening object; and a second tangential portion which has a preset angle with respect to the first tangential portion and abuts against the arc portion.

The present invention provides a looseness-prevention screw thread structure including a screw thread having a predetermined pitch, a no-load flank which is an inclined surface in a direction in which the screw thread is advanced, and a load flank which is an inclined surface in a direction in which the screw thread is retracted, the no-load flank and the load flank being formed at both sides of the screw thread, in which the no-load flank of the screw thread includes: a first tangential portion which abuts against an arc portion formed at a thread crest of an opposing fastening object; and a second tangential portion which has a preset angle with respect to the first tangential portion and abuts against the arc portion.

A method of configuring a machine (201) for production of a thread, having a pitch (227), on a workpiece (310), the machine (201) comprising: a tool (220) having a thread (223) centred on a first axis (250) and comprising one or more thread-producing peaks (225) for producing the thread having the pitch (227); and a tool holder (210) holding the tool (220), the method comprising: determining a first distance (441), in a first direction (260) parallel to the first axis (250), from a reference position (412) of the tool holder (210) to a first thread-producing peak (226) on the tool (220) when said tool (220) is held in the tool holder (210); and setting a first configuration (401) of the machine (201) wherein the reference position (412) of the tool holder (210) has a displacement (440) parallel to the first axis (250) from a reference position (411) of the workpiece (310) depending only upon: the determined first distance (441); a translation (443) parallel to the first axis (250) to account for an angular offset (340) between the first thread-producing peak (226) and a desired thread start position (311) on the workpiece (310); and an integer multiple (444) of the pitch (227).

A method of configuring a machine (201) for production of a thread, having a pitch (227), on a workpiece (310), the machine (201) comprising: a tool (220) having a thread (223) centred on a first axis (250) and comprising one or more thread-producing peaks (225) for producing the thread having the pitch (227); and a tool holder (210) holding the tool (220), the method comprising: determining a first distance (441), in a first direction (260) parallel to the first axis (250), from a reference position (412) of the tool holder (210) to a first thread-producing peak (226) on the tool (220) when said tool (220) is held in the tool holder (210); and setting a first configuration (401) of the machine (201) wherein the reference position (412) of the tool holder (210) has a displacement (440) parallel to the first axis (250) from a reference position (411) of the workpiece (310) depending only upon: the determined first distance (441); a translation (443) parallel to the first axis (250) to account for an angular offset (340) between the first thread-producing peak (226) and a desired thread start position (311) on the workpiece (310); and an integer multiple (444) of the pitch (227).

A method for producing a threaded bore in a workpiece with a tapping tool bit, which, at its drill bit tip, has a main cutting lip and a thread profile trailing in a tapping direction (I) with at least one thread cutting tooth, wherein, in a tapping stroke (G), the main cutting lip produces a core hole and, at the same time, the thread profile forms an internal thread at the inner wall of the core hole until reaching an intended thread depth (t.sub.G), specifically with a tapping feed (f.sub.G) in the tapping direction (I).

A method for producing a threaded bore in a workpiece with a tapping tool bit, which, at its drill bit tip, has a main cutting lip and a thread profile trailing in a tapping direction (I) with at least one thread cutting tooth, wherein, in a tapping stroke (G), the main cutting lip produces a core hole and, at the same time, the thread profile forms an internal thread at the inner wall of the core hole until reaching an intended thread depth (t.sub.G), specifically with a tapping feed (f.sub.G) in the tapping direction (I).