Three G's of Grinding

In talking grinding, there are three key words that will help you get what you want.

Grit. Wheels consist of bonded abrasives, particles called "grit."

Grain Size. The "grain size" of that grit identifies whether the wheel is coarse, medium, fine, or some gradation in between. The larger the grain, the coarser the wheel.

Grade. The hardness of the bond between the grains of grit determines the hardness of the wheel. Hard wheels are used for grinding soft materi­als, and soft wheels for harder materials.