Union Butterfield Straight Flute Hand Tap, Series: 1599SB, Measurement System: Metric, Coarse, M12x1.75, Semi-Bottoming Chamfer, 4 Flutes, HSS, Nitride/Steam Oxide, Class of Fit: 6H, Right Hand Cutting, 1-21/32 in Thread Length, 3-3/8 in Overall Length, 0.367 in Shank Dia, Cast Iron, Copper and Synthetic Materials Material Application, D6 Thread LimitDesigned for through or blind hole tapping with a specific cutting geometry for gray cast irons and those materials producing broken chipsAlso ideal for non-metallics, cast brass and other brass materials producing broken powdery chipsNitride and steam oxide coating reduces wear and chip welding in abrasive materialsNitriding is a process that is used to increase the hardness and wear resistance of the surface of a toolIt is particularly suitable for taps that are used on abrasive materials such as cast iron, bakeliteNitriding is used on twist drills when it is desirable to increase the strength and wear resistance of the cylindrical landsSteam tempering gives a strongly adhering blue oxide surface that acts to retain cutting fluid and prevent chip to tool welding, thereby counteracting the formation of a built-up edgeSteam tempering can be applied to any bright tool but is most effective on drills and tapsA medium alloyed high speed steel that has good machinability and good performanceHSS exhibits hardness, toughness and wear resistance characteristics that make it attractive in a wide range of applications