Patent number: 4720218
Abstract: The bit (1, 101, 201) includes a pointed tapered drill portion (10, 110, 210) with cutting edges (14, 114, 214), an abrasive frustoconical grinder portion (20, 120, 220), and an abrasive cylindrical reamer portion (30, 130, 230). The drill portion (10, 110, 210) produces a hole. The grinder portion (20, 120, 220) grinds and enlarges the hole. The reamer portion (30, 130, 230) finishes the hole. The drill portion (10, 110, 210) is carried by a shaft (12, 112, 212) that is received into an axial opening (40, 140, 240) through the grinder and reamer portions (20, 30, 120, 130, 220, 230). The drill portion (10) and grinder portion (20) may form a substantially continuous taper. In another embodiment, the drill portion (110) has an arrowhead configuration. In another embodiment, a radial slot (224) extends through the grinder portion (220), and the drill portion (210) extends axially and radially from the slot (224).
Type:
Grant
Filed:
May 1, 1987
Date of Patent:
January 19, 1988
Assignee:
The Boeing Company
Inventors:
Rene F. DeFries, Arthur D. Riley