| 摘要 |
<p>A tip (10) for a twist drill, comprising a super-hard structure (12) joined to a substrate (13) at an interface boundary (14) coterminous with an end of the substrate, the super-hard structure comprising sintered polycrystalline material comprising super-hard grains, the super-hard structure defining a super-hard end surface (15) opposite the interface boundary and a plurality of cutting edges (17, 1 shown) configured for boring into a body in use; the super-hard end surface including a centre point (16) or chisel edge, and comprising a plurality of surface regions (15A, 15B) configured such that respective planes tangential to each of the surface regions are disposed at substantially different angles from the axis of rotation of the tip in use. A precursor construction (30, Fig 6) for use in manufacturing the tip as well as a method of making the precursor construction and the tip is disclosed.</p> |
