A machining device threads a workpiece by relatively rotating the workpiece and a multi-blade tool and relatively moving them along a feed direction to perform cutting processes in the radial direction of the workpiece along the same cutting path in a predetermined spiral form. A controller performs a groove machining to form a threaded portion with vibration in the radial direction of the workpiece and a finish machining to form the threaded portion by bringing the multi-blade tool into contact with the grooved portion of the workpiece. The multi-blade tool has a first cutting blade and a second cutting blade arranged side by side along the feed direction. The controller sets amplitude of a vibration waveform to a value at which a cutting edge of the second cutting blade does not come into contact with the screw bottom surface of the workpiece in the finish machining.

A cutting insert according to one aspect has a flat plate shape including a first main surface having a polygonal shape, a second main surface located opposite to the first main surface, and an outer peripheral surface located between the first main surface and the second main surface. The cutting insert includes a cutting portion located in regions including at least a corner portion of the first main surface, and a main body portion located in a region other than the corner portion. A thickness of the main body portion is larger than a thickness of the cutting portions, and the main body portion includes a recessed portion or a protruding portion located in the outer peripheral surface thereof.

A thread cutting insert for cutting threads includes a plurality of cutting teeth disposed along a cutting portion, each cutting tooth is provided with an allocated chip former, and the chip formers are provided on a rake face of the thread cutting insert. The shape of at least two cutting teeth is different from each other. At least one cutting tooth along the cutting portion is provided with an allocated chip former the shape of which is adapted to the shape of that cutting tooth which, with respect to an order of engagement during cutting operation, precedes the subsequent cutting tooth along the cutting portion such that the at least one chip former has a shape adapted to the cross-section of chips encountered by it. A set of at least two thread cutting inserts, a thread cutting tool and a method for cutting threads, are also provided.

An indexable cutting tool stably clamps cutting inserts and prevents contact between head parts of fasteners and workpieces. Recesses with a bottom are formed in an upper surface of a cutting insert. Part of an inner wall surface of each recess curves and bulges toward a center axis of the recess. The recess is divided into first to fourth regions by a first imaginary reference plane parallel to a rotation axis of a body, and a second imaginary reference plane perpendicular to the rotation axis. The second region is on a center side and on a proximal side of the body. A tapered surface of a fastener contacts the curved surface within the second region. A center axis of the fastener inclines so a head part opposite a distal end part is closer to the center side and to the proximal side of the body than the distal end part.

A thread cutting insert for cutting threads includes a plurality of cutting teeth disposed along a cutting portion, each cutting tooth is provided with an allocated chip former, and the chip formers are provided on a rake face of the thread cutting insert. The shape of at least two cutting teeth is different from each other. At least one cutting tooth along the cutting portion is provided with an allocated chip former the shape of which is adapted to the shape of that cutting tooth which, with respect to an order of engagement during cutting operation, precedes the subsequent cutting tooth along the cutting portion such that the at least one chip former has a shape adapted to the cross-section of chips encountered by it. A set of at least two thread cutting inserts, a thread cutting tool and a method for cutting threads, are also provided.

A thread milling tool for producing a thread. The thread milling tool comprises a tool holder, which extends along a central axis and comprises a first slot-shaped cutting insert receptacle having two opposing lateral abutment surfaces and a base abutment surface arranged between the two lateral abutment surfaces and extending transversely thereto, the abutment surface forming a base of the first slot-shaped cutting insert receptacle. The thread milling tool further comprises a first cutting insert, which is fixed in the first cutting insert receptacle in a firmly bonded manner, wherein the first cutting insert comprises a base body having two opposing lateral surfaces, which abut against the two lateral abutment surfaces of the first cutting insert receptacle or are connected in a firmly bonded manner thereto, and having a lower side arranged between the two lateral surfaces and extending transversely thereto, wherein the lower surface abuts against or is connected in a firmly bonded manner to the base abutment surface of the first cutting insert receptacle, and wherein the first cutting insert comprises at least one cutting tooth that projects outwardly from the base body beyond the first cutting insert receptacle and comprises two main cutting edges for producing two opposing flanks of the thread.

A thread milling system includes a thread milling machine having a spindle; and a combination tool having a body and a reaming insert, the body having a first end and a second end, the body defining a securing pocket, the reaming insert secured proximate to the second end of the body and within the securing pocket, the second end of the body attached to the spindle.

A thread milling tool includes a tool body with at least one pair of insert seats including of a first insert seat and a second insert seat, which are angularly and axially offset from each other, and several double-sided thread milling inserts. Each thread milling inserts is adapted to the first and second insert seats such that it is mountable in the first insert seat in one single working position with a first group of cutting edges on a first side of the thread milling insert in an active cutting position, and mountable in the second insert seat in one single working position with a second group of cutting edges on an opposite second side of the thread milling insert in an active cutting position. A thread milling insert suitable for use in such a thread milling tool is also provided.

A method of operating a thread milling machine includes securing a product in a securing mount proximate to the thread milling machine, the thread milling machine having a spindle; securing a combination tool to the spindle, the combination tool having a body and an insert, the body having a first end and a second end, the body defining a securing pocket, the insert secured proximate to the second end at a first side of the securing pocket, the second end attached to the spindle; and rotating the spindle.

An indexable cutting tool that allows for stable clamping of cutting inserts and prevents contact between head parts of fastening members and workpieces is provided. Recesses with a bottom are formed in an upper surface of the cutting insert. At least part of an inner wall surface of the recess is a curved surface bulged toward a center axis of the recess. When the recess is divided into four, first to fourth, regions by a first imaginary reference plane parallel to a rotation axis of a body and a second imaginary reference plane perpendicular to the rotation axis, the second region is located on a center side and on a proximal side of the body. A tapered surface of the fastening member makes contact with the curved surface within the second region. A center axis line of the fastening member is inclined such that the head part opposite from a distal end part is located closer to the center side and to the proximal side of the body than the distal end part.