| 摘要 |
A drill bit with an axially elongated shank is suitable for use in all known conventional hand-held drilling machines. The shank is generally cylindrically shaped with axially extending first grooves open at the free rear end face of the shank. Axially extending second grooves are superimposed at least in part on the first grooves and are spaced from the rear end face. Each second groove forms at least one shoulder face disposed transversely of the shank axis and oriented in the direction facing oppositely to the rear end face. Accordingly, the drill bit, due to its first grooves, can be utilized in the chucks presently used in drilling machines and percussion drilling machines. Further, due to the second grooves, the drill bit can be clamped for limited axial movement in the chucks of known hammer drills. |
