... 3.ISO9001:2000 Certificate precision tungsten carbide ball for CNC machine . Precision tungsten carbide balls and valve seats* High strength, high ... tolerances of dimensions have respectively reached the standards of the machine industry: G5, G10, G16, G40 and G100 of JB/T ... their good precision, good wear resistance and good corrosion resistance. Type and specifications Dia.(D)Inch3/47/815/1611 1/81 ...