Our 3M diamond phono point tool features sharp, sturdy diamonds used for internal radii dressing applications. This tool is for general toolroom dressing on concave and convex small diameter grinding wheels. For small diameter, fine grit grinding wheels our 3M diamond phono point tool is engineered to dress with precision their internal radii and more intricate forms. Our phono point tool is manufactured using the finest quality diamonds and durable steel for consistent cutting, life and quality. This tool features a 1/8 x 1 in shank and diamond at 60, 75 or 90 deg angles. Cost effective use of diamond and CBN wheels requires truing and dressing, two distinct and necessary functions truing restores the shape of the diamond or CBN wheel. Dressing prepares the wheel for aggressive action. This function is necessary after a wheel is trued. Truing generally leaves the grinding surface of a wheel smooth and unable to remove material from a workpiece effectively. Dressing removes some of the bond material from the surface of a trued wheel to expose the diamond crystals and make the wheel grind efficiently. Dressing also removes tiny pieces of material from the pores of the wheel face to prevent loading, which can cause vibration and leave burn marks on the workpiece.