1/4"-28 UNF HSS-EV SP/PTTAP-OXIDISED

With straight flutes and short fluted helix at point. Ideal for tapping through holes as swarf is directed ahead of the tap. Flutes are narrower than those of taps required to pull swarf towards the shank and act as lubricant channels, giving greater tap rigidity. Manufactured to BS 949: Part 4: 1990 and ISO 529 : 1975. Tolerance 2B.
Oxidised finish (black): special heat treated finish gives resistance to rust and reduces metal to metal friction. Combined with a porous surface that gives optimum lubricant retention, work-generated heat is minimised, giving prolonged cutting edge life. Use on higher carbon steels cast materials high silicon aluminiums.