Patent ID: 8851058

Claim:
A tool comprising a carrier element comprising an outer circumferential edge; and a grinding element comprising: abrasive particles embedded in a metal matrix having a network of interconnected pores; a first face; a second face; a grinding edge between the first face and the second face, where the grinding edge wears in use; a bonding edge between the first face and the second face and opposite the grinding edge, where the bonding edge of each grinding element is bonded to the outer circumferential edge of the carrier element; a height H equal to the distance between the grinding edge and the bonding edge; a first indicator mark disposed on the first face of the grinding element; and a second indicator mark disposed on the first face of the grinding element, wherein the first and second indicator marks comprise arc segments that each have a height h, are parallel to one another and are both parallel to the outer circumferential edge of the carrier element, wherein the first and second indicator marks run the full length of the grinding element, and wherein the first and second indicator marks partition the grinding element into three segments having a height equal to (H−(2×h))/3.