Stepped drill construction
US4582458A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 9, 1984 |
| Grant date | Apr 15, 1986 |
| Priority date | — |
| Expiry date | Aug 9, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T408/906
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
Drill bit for drilling holes of different diameters which has a series of cylindrical outer surfaces of increasing diameter from the outer to the inner end of the drill bit. A beveled conical surface interconnects each adjacent pair of cylindrical surfaces. At least two flutes are machined at two circumferentially spaced locations to provide two cutting edges on each diameter of the drill. At each cutting edge the cylindrical surfaces are relieved radially and the conical surface is relieved axially over an acute circumferential angle. The major peripheral portions of the cylindrical and conical surfaces for each diameter are respectively concentric to the axis of the drill and of zero pitch angle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.