Wipe the label located on the top of a grinding wheel with a rag if you cannot read the numbers printed on the label.
Set an identification chart for the grinding wheel next to the grinding wheel. Not all manufacturers use the same coding system and although the specifications are listed in the same order, the meanings of the printed numbers may vary.
Read the first set of digits to determine the type of grit used in the construction of the grinding wheel.
Move to the second set of numbers that designate the grit size of the wheel. Smaller numbers mean a coarser grit. For example, if the second sets of numbers were 60, it would designate a medium-grained grinding wheel.
Read the lone third letter to determine the hardness of the bond between the grit. Letters closer to the letter A represent a softer bond, hardness increases as the letters move through the alphabet to the letter Z.
Compare the last letter in the printed identification series to determine the bonding material used in the grinding wheel. Common binding agents are resin (B), vitrified (V) and rubber (R.) The letter F paired with the bonding agent identification means a fiber glass reinforced grinding wheel.