# US 10,562,118 B2 · Tapered pipe thread-machining spiral tap > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,562,118 B2 - Document ID: US10562118B2 - Status: Granted - Kind: B2 - Application number: 15/773,226 - Filed: 2015-12-02 - Published: 2018-11-08 - Granted: 2020-02-18 - Earliest claimed: 2015-12-02 - Assignees: Osg Corporation - Applicants: Osg Corporation - Inventors: Takayuki Nakajima - Web page: https://patentgrep.com/patent/US10562118B2 ## CPC - B23G 5/06: Taps (chucks therefor B23B31/00) - B23G 2200/26: Coatings of tools - B23G 2200/28: Threading tools having a conical form - B23G 2200/30: Cutting edges that are rounded in the cross-sectional view of the cutting edge - B23G 2200/34: Tools having an increasing diameter in the direction of the shank from the tip (B23G2200/28 takes precedence) - B23G 2200/48: Spiral grooves, i.e. spiral flutes - B23G 2225/56: Titanium carbide nitride (TiCN) - B23G: THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH (making helical grooves by turning B23B5/48, by milling B23C3/32, by forging, pressing, or hammering B21K1/56, by grinding B24B19/02; arrangements for copying or controlling B23Q; thread-forming by corrugating tubes B21D15/04, by rolling B21H3/02) ## Abstract A pipe-tapered-thread machining spiral tap includes a tapered thread portion that is circumferentially divided by flutes into a plurality of lands. Each of at least one of the lands has a cutting edge that extends along a corresponding one of the flutes. The flutes are made of a plurality of spiral flutes that are three, four or five spiral flutes each having a helix angle that is not smaller than 30° and smaller than 50°. A flute width ratio AG/(AG+AL) is 0.3-0.5, where AG represents a central angle which is subtended by each of the flutes and which is defined at a center corresponding to the rotation axis in a cross section that is perpendicular to the rotation axis, and AL represents a central angle which is subtended by each of the lands and which is defined at the center in the cross section. ## Claims ### Claim 1 A spiral tap that is to be rotated about a rotation axis for machining a pipe tapered thread, said spiral tap comprising a tapered thread portion having a thread profile that becomes from an incomplete profile to a complete profile in a direction away from a distal end of a chamfered portion toward a complete thread portion, said tapered thread portion being circumferentially divided by flutes into a plurality of lands, each of at least one of said lands having a cutting edge that is defined by one of opposite ends of said each of said at least one of said lands which is located on a front side of the other of said opposite ends in a direction of rotation of said spiral tap, such that said cutting edge extends along a corresponding one of said flutes, wherein said flutes consist of a plurality of spiral flutes that are three, four or five spiral flutes each having a helix angle that is not smaller than 30° and smaller than 50°, and a flute width ratio AG/(AG+AL) is 0.3-0.5, where AG represents a central angle which is subtended by each of said flutes and which is defined at a center corresponding to said rotation axis in a cross section that is perpendicular to said rotation axis, and AL represents a central angle which is subtended by each of said lands and which is defined at said center in said cross section. ### Claim 2 (depends on 1) The spiral tap according to claim 1, wherein said spiral flutes consist of four spiral flutes and said lands consist of four lands defined by said four spiral flutes, and said cutting edge is provided in every other of said four lands as said at least one of said lands in a circumferential direction of said spiral tap. ### Claim 3 (depends on 1) The spiral tap according to claim 1, wherein said tapered thread portion defines a right-hand tapered thread, and said plurality of spiral flutes are right-hand spiral flutes. ### Claim 4 (depends on 1) The spiral tap according to claim 1, wherein said tapered thread portion defines a left-hand tapered thread, and said plurality of spiral flutes are left-hand spiral flutes. ### Claim 5 (depends on 1) The spiral tap according to claim 1, wherein each of said at least one of said lands has a back edge that is defined by said other of said opposite ends of each of said at least one of said lands which is located on a front side of said one of said opposite ends in a direction opposite to said direction of rotation of said spiral tap, such that said back edge extends along a corresponding one of said flutes; and a rake angle of said back edge is smaller than a rake angle of said cutting edge. ### Claim 6 (depends on 5) The spiral tap according to claim 5, wherein a relieved surface is defined in said chamfered portion, such that a radial distance from said rotation axis to said relieved surface is reduced in a direction opposite to said direction of rotation of said spiral tap in an entire region from said cutting edge to an intermediate position in a width of each of said at least one of said lands, and such that said radial distance is constant in said direction opposite to said direction of rotation of said spiral tap in a region from said intermediate position to said back edge. ### Claim 7 (depends on 1) The spiral tap according to claim 1, wherein at least said chamfered portion and said complete thread portion are covered with a titanium carbonitride TiCN film.