Explanation of icons E High speed steel Nitriding/Oxidizing 2D Cutting length Nitride Oxide High speed steel Coating Coated Spiral pointed tap through hole use High speed steel For blind hole with Hand tap (Cobalt HSS) through coolant hole Powder HSS For through hole with Spiral fluted tap radial coolant hole through hole use Ultra micro grain For left hand thread Spiral fluted tap cemented carbide blind hole use Left hand For synchronized Low spiral Alloy steel feeding fluted tap blind hole use Tool Low spiral fluted tap Tool steel Number of threads blind hole use steel on chamfer specially for horizontal tapping Front face Number of threads Carbon steel and low alloy steel Specification Oxidizing on chamfer IS P (for Round Die) 5 〜10 Tapping Speeds Oxide (m/min) Nitriding Center drills left hand cut Nitride COLOUR RINGS YELLOW for sticky and soft steel ≤500N/mm2 BLUE (VA) for stainless steel and general steel RED for hard steel 30~45 HRC WHITE for cast iron ORANGE for nickel base alloy, alloy steel (CrMo, NiCrMo) and stainless steel (V4A) PINK for titanium alloy, alloy steel (CrMo, NiCrMo) ≥950N/mm2 GREEN for aluminium casting and diecasting (Si≤12%) 50