Identifying your diamond or CBN wheel

Diamond and CBN wheels are classified by their shape, grit size, concentration and the bond.   A typical diamond wheel specification might be D1A1-150C100B where D1A1 is the wheel shape, 150 is the grit size, 100 is the concentration and B is resin bond.

Grit sizes of 120 to 180 are typical for tool room applications.   Finer grits of 220 or above are generally special order and for extremely fine finish work.

The concentration is simply the amount of grit in the mix.   Concentrations of 75 or higher are preferred but it also depends on the specific application.   Some jobs may do better with less concentration. The most common are concentrations of 75 for resin bond grinding wheels and 175 or 200 for vitrified grinding wheels. Generally, the higher the concentration the longer the wheel will last and the more expensive it will cost up front.

Bonds are weak or strong depending on the application but usually there is one main bond for 90% of the wheels made. Typically, a manufacturer will need to know if a diamond wheel will be run in coolant or dry -- This determines the bond.   CBN wheels should always be run in coolant.

You will also see in the specification a callout for the bond layer thickness, for example: "X=1/8".   This is very important in the life of the wheel and its initial cost.   A bond layer of 1/8" thick will be half the thickness of 1/4" thick and thus half the life.   Some manufacturers will supply wheels with as little as 1/16" or as much as 1/2".   The layer thickness also depends on the application.   The price can vary dramatically and this is an important factor to consider when comparing wheels from one company to another.