Hardness
The term "hardness of grinding wheels" does not refer to the abrasive grain, but designates the resistance odf the bond to grains being removed during the grinding process. |
Grain Size
The assignement of numbers to specific grain size distributions has been determined on the basis of an internationally applicable standard. Extremly fine grains (micro-grains: approx. grain 240) are otained by sedimentation. Finer grains are less brittle and harder to break out of a bond. For this reason, a wheel with fine grains appears harder than a wheel within the identical range of wheel hardness but with coarse grains. |
