Low torque tap
US7144208B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 2004 |
| Grant date | Dec 5, 2006 |
| Priority date | — |
| Expiry date | Jul 2, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T408/9048
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A low torque tap includes a shank portion with a driving square and a thread cutting portion. The thread cutting portion includes a threaded body with one or more asymmetrical straight flutes that run essentially parallel to a longitudinal axis of the tap. The thread cutting portion also includes one or more short angular flutes or spiral points and a tapered chamfer. For tapping steel alloys, the cutting edges of the straight flutes and the spiral points have a rake or chordal hook angle of between about 5 and 15 degrees. For tapping ferrous materials, the tap is made from molybdenum-enriched high-speed steel and may be coated with a wear-resistant, friction-reducing layer. A second, outer layer, such as molybdenum disulfide, may be applied over the wear-reducing layer for further reduction in friction. For tapping non-ferrous materials, the tap may be coated with a layer of material containing carbon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.