# US 7,147,413 B2 · Precision cemented carbide threading tap

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 7,147,413 B2
- Document ID: US7147413B2
- Status: Granted
- Kind: B2
- Application number: 10/375,730
- Filed: 2003-02-27
- Published: 2004-09-02
- Granted: 2006-12-12
- Earliest claimed: 2003-02-27
- Assignees: Kennametal Inc.; Yamawa Mfg. Co., Ltd.
- Inventors: Willard E. Henderer; Sadayuki Akaki
- Web page: https://patentgrep.com/patent/US7147413B2

## CPC

- B23G 5/06: Taps (chucks therefor B23B31/00)
- B23G 2225/28: Hard metal, i.e. cemented carbides
- Y10T 408/78: Tool of specific diverse material
- Y10T 408/9048: Extending outwardly from tool-axis
- 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)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A precision cemented carbide threading tap is designed for use in precision tool holders in synchronous high speed tapping. The precision tap includes a fully cylindrical shank without the aid of squares, flats or other notches. The precision tap further includes a threaded body portion and a threaded cutting chamfer portion. The threaded body portion and the threaded cutting chamfer portion of the precision tap are concentric to the cylindrical shank of the tap within a runout of 10 microns. The precision cemented carbide threading tap improves the accuracy, life and speed by which internal screw threads are produced.

## Claims

### Claim 1

A precision cemented carbide tap, comprising:
an axially rearward end including a cylindrical shank; and
an axially forward end including a threaded body portion and a threaded cutting chamfer portion,
wherein said precision cemented carbide tap is coated with a first wear resistant layer of metal nitrides, carbides, carbonitrides, borides and/or oxides, and wherein the metal is chosen from one or more of the following: aluminum, silicon and the transition metals from Groups Iva, Va, and VIa of the Periodic Chart, and
wherein the cylindrical shank is held by precision hydraulic holders during grinding such that the threaded body portion and the threaded cutting chamfer portion are concentric to the cylindrical shank within a runout of 10 microns.

### Claim 2 (depends on 1)

The carbide tap coated according to claim 1, further comprising a second, outer layer applied to the first wear resistant layer for reducing friction.

### Claim 3 (depends on 2)

The carbide coated tap according to claim 2, wherein the outer layer is comprised of molybdenum disulphide; molybdenum disulphide and transition metals, or any combination thereof.

### Claim 4 (depends on 2)

The carbide coated tap according to claim 2, wherein the outer layer is comprised of carbon; carbon and transition metal carbides, or any combination thereof.

### Claim 5 (depends on 2)

The carbide coated tap according to claim 2, wherein the outer layer is comprised of carbon and a transition metal, or any combination thereof.

### Claim 6 (depends on 2)

The carbide coated tap according to claim 2, wherein the outer layer is comprised of carbon nitride.

### Claim 7 (depends on 2)

The carbide coated tap according to claim 2, wherein the outer layer is deposited as a single layer or in multiple layers.