General Views: 19

Hardness of common countersink materials: 1) Standard HSS - HRC62-64, suitable for carbon steel, aluminum, copper and other ordinary materials; 2) Cobalt HSS (HSS-E) - HRC65-67, good red hardness, suitable for stainless steel, mold steel, alloy steel and other hard-to-machine materials; 3) Carbide - HRA90+ (equivalent HRC90+), very wear-resistant, for hardened steel, superalloys and other ultra-hard materials. Harder is not always better: 1) Harder tools wear less but are more brittle and chip easily - unsuitable for high-impact or interrupted cutting; 2) Softer tools are tougher and resist chipping but wear faster and have shorter life; 3) Choose hardness by material and conditions rather than always going hardest. General rule: soft materials (aluminum, copper, plastic) - standard HSS is enough; medium hardness (carbon steel, alloy steel) - high-performance cobalt HSS; high hardness (hardened steel, superalloys) - carbide. For heavy impact or interrupted cutting choose toughness; for continuous cutting and finishing choose hardness.