A method of producing a rotationally orientated thread starting at a desired angular position and suitable for mass production is provided. The method is particularly suitable for improving the angular positioning of spark plugs in car engines. The method involves measuring precisely the length (L) of the tool (13) and the distance, at a particular angular position, of a full thread form (14) of the thread to the tip, so that its start position at the tip can be calculated. Using that distance as an offset of the length of the tool reported to the CNC machine, and starting from its reference position, it commences producing the thread (12) in the bore (11) at the desired angular position of the bore (11).

A method for making a screw hole in a workpiece including a plate-shaped portion includes: preparing an auxiliary member having a flat plate shape; forming, in the plate-shaped portion, a first pilot hole having a minor diameter smaller than a major diameter of the screw hole; forming, in the auxiliary member, a second pilot hole having a minor diameter smaller than the major diameter of the screw hole; fixing the auxiliary member to the plate-shaped portion so that the first pilot hole is concentric with the second pilot hole; and making the screw hole in the plate-shaped portion and the auxiliary member by inserting a tap in the first pilot hole and the second pilot hole.

A method for making a screw hole in a workpiece including a plate-shaped portion includes: preparing an auxiliary member having a flat plate shape; forming, in the plate-shaped portion, a first pilot hole having a minor diameter smaller than a major diameter of the screw hole; forming, in the auxiliary member, a second pilot hole having a minor diameter smaller than the major diameter of the screw hole; fixing the auxiliary member to the plate-shaped portion so that the first pilot hole is concentric with the second pilot hole; and making the screw hole in the plate-shaped portion and the auxiliary member by inserting a tap in the first pilot hole and the second pilot hole.

A metal insert having a body at a base diameter, a plurality of retention regions spaced apart and extending radially from the body, and an end effector at one end, for engaging a mating member. Each retention region consists of a circumferential series of alternating prongs and recesses. The insert is manufactured by selecting or processing a solid raw bar to produce an engineered rod having a plurality of axially continuous protrusions at a protrusion diameter alternating circumferentially with a plurality of axially continuous channels at a channel diameter. At axial intervals, the diameter of the engineered rod is decreased with a form tool to a base diameter smaller than the channel diameter, thereby producing a featured rod having a series of axially alternating spacer regions at the base diameter and radially outwardly extending feature regions consisting of a circumferential series of alternating prongs and recesses.

A metal insert having a body at a base diameter, a plurality of retention regions spaced apart and extending radially from the body, and an end effector at one end, for engaging a mating member. Each retention region consists of a circumferential series of alternating prongs and recesses. The insert is manufactured by selecting or processing a solid raw bar to produce an engineered rod having a plurality of axially continuous protrusions at a protrusion diameter alternating circumferentially with a plurality of axially continuous channels at a channel diameter. At axial intervals, the diameter of the engineered rod is decreased with a form tool to a base diameter smaller than the channel diameter, thereby producing a featured rod having a series of axially alternating spacer regions at the base diameter and radially outwardly extending feature regions consisting of a circumferential series of alternating prongs and recesses.

Disclosed herein is a system for fastening an anchor in a borehole in a mineral substrate, in particular concrete, mortar or masonry, comprising an anchor having a core section and a thread section, and a grooving tool for grooving an internal thread in the borehole, the grooving tool comprising the following: a base body having a leading and a trailing end, a force application device being provided, via which a torque for screwing the grooving tool into the borehole and for grooving the thread is transmitted to the base body, the base body having an outer surface on which a grooving thread is formed, which is suitable for grooving the internal thread into the wall of the borehole, the following applying to the ratio of the length h.sub.eff of the thread section of the anchor and the nominal diameter d.sub.b of the borehole: h.sub.eff/d.sub.b10.0, preferably 12.0, particularly preferably 15.0, and in particular 30.0.

Disclosed herein is a system for fastening an anchor in a borehole in a mineral substrate, in particular concrete, mortar or masonry, comprising an anchor having a core section and a thread section, and a grooving tool for grooving an internal thread in the borehole, the grooving tool comprising the following: a base body having a leading and a trailing end, a force application device being provided, via which a torque for screwing the grooving tool into the borehole and for grooving the thread is transmitted to the base body, the base body having an outer surface on which a grooving thread is formed, which is suitable for grooving the internal thread into the wall of the borehole, the following applying to the ratio of the length h.sub.eff of the thread section of the anchor and the nominal diameter d.sub.b of the borehole: h.sub.eff/d.sub.b10.0, preferably 12.0, particularly preferably 15.0, and in particular 30.0.

The invention relates to methods for producing a thread with a predetermined thread pitch in a workpiece.

The invention relates to methods for producing a thread with a predetermined thread pitch in a workpiece.

The thread generating tool for producing a thread in a workpiece has the following features: a) the tool is rotatable about a tool axis (A), b) the tool has a number n1 of groove generating regions for generating in each case one groove in the workpiece and a number m1 of thread generating regions for generating the thread in the workpiece, c) each of the m thread generating regions is arranged behind one of the n groove generating regions as viewed in an axial projection parallel to the tool axis (A), and has a smaller extent than said groove generating region as viewed in cross section in the axial projection.