If the material to be machined is hardened or very tough, diamond tools are often used. These tools are available in various shapes and designs. Diamond tools also have a diamond grain embedded in a bond. This bond can be a synthetic resin or a metallic bond. These so-called CBN tools have a wide range of applications.
The most commonly used diamond tool is the steel backing onto which the diamond grain is applied using an electroplating process. The grain size is expressed according to a special standard called FEPA. This standard represents the grain size measured in microns. The designation D126 is a popular grain size, representing a grain size of approximately 100µ.