| 摘要 |
<p>A depressed-centre grinding wheel (10) comprising at least a circular cutting annulus (15) made of a substantially planar compacted abrasive material lying on a plane that is perpendicular to the rotation axis of the grinding wheel (10) and a concave central portion (16) provided with a central through-hole (12) for attachment, in which the internal diameter (Di) of the circular annulus (15) coincides with the external diameter of the concave portion (16), is not greater than 60 mm.</p> |
