Method for producing a workpiece threaded hole

A method for producing a workpiece threaded hole by a tapping tool, with a drilling stroke, comprising:

• driving a rotating tapping tool into a workpiece in a drilling direction to a nominal drilling depth, and so forming a thread-free pilot hole, and with a tapping stroke in which the tapping tool produces an internal thread in the pilot hole with a tapping feed rate and a tapping speed synchronized therewith, wherein for preparing the tapping stroke, a first reversing stroke takes place after the drilling stroke, in which the tapping tool is guided out of the pilot hole in a reversing direction opposite to the drilling direction to such an extent, wherein the tapping tool is radially displaced in an offset stroke by a radial offset, wherein in the tapping stroke, the radially controlled, rotating tapping tool is guided in a circular rotary motion along a circular path about a hole axis, and wherein, in the tapping stroke, the tool rotation and the tool circular motion take place in the same direction of rotary motion and at the same rotational speed;
• wherein the tapping tool has a thread generating section;
• wherein the thread generating section of the tapping tool has at least one, or several, thread teeth, and/or wherein each tooth lies on its own tooth contour diameter, wherein the allowance between two successive thread teeth is equal to the difference of the tooth contour diameters of the two successive thread teeth, and/or wherein a machining tooth lagging behind in a direction of rotation as the last machining tooth is a finishing tooth, a tooth contour diameter of which is larger than a tooth contour diameter of the preceding machining tooth, and/or wherein the thread teeth lie on an envelope curve;
• and
• wherein the tapping stroke and the drilling stroke have an identical stroke direction, and/or wherein during the tapping stroke, a thread generating section of the tapping tool generates the internal thread down to a nominal thread depth, and wherein the tapping stroke is extended by a free-cutting stroke when the nominal thread depth is reached, in which the feed and the speed of the tapping tool are no longer synchronized with one another and a circumferential free-cutting groove adjoining the internal thread and without thread pitch is produced.