New 3M™ Silver Depressed Centre Grinding Wheels. Discover a new class of right-angle abrasives. Triangular ceramic grains have a self-sharpening ability to retain their sharpness in three steps. During grinding, the surface heats up slower, producing less smoke and leftovers. It also needs less pressure to perform the task, allowing the operator to finish the task with less fatigue. 3M™ Silver wheels are an ideal choice for applications like weld removal, bevelling, edge chamfering and more – offering a faster cut and longer life than aluminium oxide and alumina zirconia wheels.