Exact-Step-Drill-Bits-with-Spiral-Flute-Ti AIN-Exact-07021-P-Ideal-for-burr-free-drilling-&-reaming-of-sheet-metal-pipes-&-profiles-&-manufactured-with-Ti Al N-titanium-aluminium-nitride-coating-optimum-for-stainless-steel-machining-surface-hardness-approx-3000-HV-Also-features-Chamfering-deburring-zone-drilling-&-deburring-in-one-work-step-P-Exact-07021-Step-Drill-With-Spiral-Flute-Ti AIN-Bore-Diameter-4-12mm