"IRWIN" HIGH CARBON STEEL BOTTOM TAP *1/2"-13NC *Use with 27/64" drill bit *1 to 2 threads chamfered *Ideal for threading close to the bottom of blind holes *High carbon steel *For hand tapping applications *Chip breaking technology cuts chips easier *Tap size and recommended drill bit size are laser etched on each tap *Taps produce a class 2B thread *Carded