Diamond or CBN* abrasive grains electroplated on quality steel mandrels. Shanks of hardened ground steel for assured concentricity, no truing required. Used for ID, jig or contour grinding. For best results, choose a mandrel sized at 70-80% of the hole diameter. Coolant is optional, but enhances performance; should be oil-based for CBN mandrels.
*Cubic boron nitride (CBN) is the second hardest known material, surpassed only by diamonds.