The purpose of this standard is to establish a common basis for checking the size of diamond and cubic boron nitride (CBN) grain for use in the manufacture of diamond grinding wheels, saws and other industrial diamond products. It is intended to serve as a common basis of understanding for diamond grain producers, and for the manufacturers, distributors, and users of these abrasive products. This standard sets out the grit size designations, the size limits and the sieves to be used in determining them, as well as the test procedure for use by industry in checking the size of diamond grain exclusive of any coating which would have to be removed before performing the test. Diamond and CBN grain is a natural or manufactured substance which is produced or reduced by crushing to specific grit sizes.