| 摘要 |
A drill blank, particularly a blank for a micro-drill, comprises an elongate cylindrical cemented carbide body, having flat end surfaces, a recess formed in one end surface and taking the form of an island in that surface wholly surrounded by cemented carbide, and an abrasive compact located in the recess, bonded to a cemented carbide, and presenting a surface coincident with the carbide end surface in which the recess is located. A drill may be formed from the drill blank by suitably shaping the cemented carbide body, for example, by fluting, in the region of the abrasive compact to expose the abrasive compact. <IMAGE> |
