Dormer HSS Bright UNF UNF Hand Tap Straight Flute ANSI 5/8 inch x 18, size 5/8NO3. The most versatile taps for hand use or machine tapping in a wide variety of materials in through or blind hole applications. Available in 3 chamfer lenghts - taper, plug and bottoming. Premium substrate with bronze oxide body and shank reduces rust and corrosion. Bright finish flutes improve chip flow in soft or non-ferrous materials.