OSG Threading Tap - UNF Spiral Flute HSS-E - Steam Oxide Coated - Blind Hole - 5/8 x 18The OSG UNF Spiral Flute Threading Tap in 5 8 x 18 UNF is built for precise blind hole threading, delivering clean, accurate threads in challenging metals. Designed for professionals who need dependable performance in critical machining tasks. Thread Type and Size: UNF spiral flute threading tap, 5 8" diameter with 18 TPI (5 8 x 18 UNF) Material: HSS E (high speed steel with cobalt) for enhanced hardness and heat resistance Coating: Steam oxide