R8 Shank Tools Catalog Numbering System How Do Catalog Numbers Work? Each character in our catalog number signifies a specific trait of that product. Use the following key columns and corresponding images to easily identify which attributes apply. R8DA188181 R8 DA 188 181 Shank Toolholder Toolholder Tool Style Style Size Length DA = Double-angle collet (Tool gage line chuck to front of tool) EM = End mill adapter SM = Shell mill adapter inchxxx = x.xx DA = Collet series xxx (188) EM = I.D. size: metric — xx = xx, (20); inch — xxx = x.xx, (075) SM = O.D. size: metric — xx = xx, (20); inch — xxx = x.xx, (075) WWW.WIDIA.COM G25