Straight Flute Taps Greenfield Threading Flute Count 4 1/2-20 UNF 4 Flute H5 Semi-Bottoming HSS-E CNC For Cast Iron & Harder Materials CNC Straight Flute Tap- Steam Oxide over Nitride Greenfield Threading List HTHM CNC Straight Flute Taps Threads per Inch 20 Thread Cutting Part Length 15/16 inch Overall Length 3-3/8 inch Thread Diameter Size 1/2 inch