A method of manufacturing a threaded hole in a workpiece includes providing the workpiece having a region with a hole. The method also includes cutting a threading for the hole. Furthermore, the method includes, independent of cutting the threading, densifying the region proximate the hole to reduce material porosity in the region.

Provided are a control device and a control method for a machine tool which are capable of further reducing a command-waiting time. This control device for a machine tool which controls synchronized operation of a main shaft and a feed shaft comprises: a numerical value control unit; a main shaft control unit; a rotation detection unit. The numerical value control unit has a main shaft command output unit which, when a cutting operation and pulling-out operation are carried out from a machining start position to a target position an arbitrary number of times, acquires from the tapping program the rotation amount and the maximum rotation speed of the main shaft in the cutting operation and pulling-out operation and which supplies the rotation amount and the maximum rotation speed of the main shaft to the main shaft control unit as the main shaft command.

Provided are a control device and a control method for a machine tool which are capable of further reducing a command-waiting time. This control device for a machine tool which controls synchronized operation of a main shaft and a feed shaft comprises: a numerical value control unit; a main shaft control unit; a rotation detection unit. The numerical value control unit has a main shaft command output unit which, when a cutting operation and pulling-out operation are carried out from a machining start position to a target position an arbitrary number of times, acquires from the tapping program the rotation amount and the maximum rotation speed of the main shaft in the cutting operation and pulling-out operation and which supplies the rotation amount and the maximum rotation speed of the main shaft to the main shaft control unit as the main shaft command.

A tap phase detection method includes: acquiring a relation between a rotation angle and an existence of a screw thread by measuring a position of the screw thread of a tap with a sensor from a direction intersecting with an axial direction of the tap while rotating the tap; and detecting a phase of the tap based on the acquired relation between the rotation angle and the existence of the screw thread.

A tool coupling device for coupling a tool can comprise a drive shaft for coupling to the drive, an output shaft for coupling to the tool, the output shaft being rotatable about a central axis (A), a transmission unit connected between the drive shaft and the output shaft and translating a rotational movement of the drive shaft at an input speed (n.sub.S) into a rotational movement of the output shaft at an output speed (n.sub.W) greater than the input speed (n.sub.S) and a non-rotating housing, wherein the transmission unit, and at least a part of the input shaft and a part of the output shaft that are both coupled to the transmission unit, are arranged within the housing, wherein the drive shaft is rotatably mounted on the housing; and wherein the output shaft is rotatably supported solely on the input shaft and is not rotatably supported on the housing.

A tool coupling device for coupling a tool can comprise a drive shaft for coupling to the drive, an output shaft for coupling to the tool, the output shaft being rotatable about a central axis (A), a transmission unit connected between the drive shaft and the output shaft and translating a rotational movement of the drive shaft at an input speed (n.sub.S) into a rotational movement of the output shaft at an output speed (n.sub.W) greater than the input speed (n.sub.S) and a non-rotating housing, wherein the transmission unit, and at least a part of the input shaft and a part of the output shaft that are both coupled to the transmission unit, are arranged within the housing, wherein the drive shaft is rotatably mounted on the housing; and wherein the output shaft is rotatably supported solely on the input shaft and is not rotatably supported on the housing.

A method of manufacturing a threaded hole in a workpiece includes providing the workpiece having a region with a hole. The method also includes cutting a threading for the hole. Furthermore, the method includes, independent of cutting the threading, densifying the region proximate the hole to reduce material porosity in the region.

A method of manufacturing a threaded hole in a workpiece includes providing the workpiece having a region with a hole. The method also includes cutting a threading for the hole. Furthermore, the method includes, independent of cutting the threading, densifying the region proximate the hole to reduce material porosity in the region.

The tap tool (10) has an axis of rotation (Cr) and machines a pilot hole (6′) so that the same becomes a screw hole (6) in a state where the axis of rotation has been matched to a central axis (C6) of the pilot hole which is provided to a workpiece, wherein the tap tool (10) is characterized by being provided with: a thread section (14) having a blade section (14a) for machining a thread groove of the screw hole; pad sections (15, 16) located behind in a direction of rotation of the blade section, and engaging with the thread groove machined by the blade section during the machining of the thread groove; and a non-engagement section (17) for forming a space (20) between said section and the screw hole in a cross-sectional view where the axis of rotation and the central axis of the screw hole have been matched. The space has a size that enables simultaneous release of the engagement between the thread section and the thread groove and the engagement of the pad sections and the thread groove, in a case where the tap tool has shifted in a direction orthogonal to the axis of rotation within the screw hole, such shift being from the state where the axis of rotation and the central axis of the screw hole have been matched.

The tap tool (10) has an axis of rotation (Cr) and machines a pilot hole (6′) so that the same becomes a screw hole (6) in a state where the axis of rotation has been matched to a central axis (C6) of the pilot hole which is provided to a workpiece, wherein the tap tool (10) is characterized by being provided with: a thread section (14) having a blade section (14a) for machining a thread groove of the screw hole; pad sections (15, 16) located behind in a direction of rotation of the blade section, and engaging with the thread groove machined by the blade section during the machining of the thread groove; and a non-engagement section (17) for forming a space (20) between said section and the screw hole in a cross-sectional view where the axis of rotation and the central axis of the screw hole have been matched. The space has a size that enables simultaneous release of the engagement between the thread section and the thread groove and the engagement of the pad sections and the thread groove, in a case where the tap tool has shifted in a direction orthogonal to the axis of rotation within the screw hole, such shift being from the state where the axis of rotation and the central axis of the screw hole have been matched.