HSS Cobalt Twist Drill Bits

EXTRACUT HSS-Cobalt (Co5% / Co8%) Twist Drill Bits the highest tier of conventional HSS drilling technology, engineered specifically for drilling tough, heat-resistant, and work-hardening materials where standard HSS drills fail prematurely. The cobalt alloy addition significantly improves red hardness, allowing these drills to maintain their cutting edge at temperatures exceeding 650°C.

Key Features

• Cobalt Alloy (5% / 8% Co) — Cobalt content increases red hardness temperature threshold to 650–700°C, enabling sustained cutting in heat-resistant steels and hardened materials.
• Superior Hot Hardness — Maintains 60+ HRC hardness at elevated temperatures where standard M2 HSS would soften and fail rapidly.
• Work-Hardening Material Compatible — Specifically formulated to penetrate austenitic stainless steels (304/316), Inconel, Monel, and other work-hardening alloys without rapid edge degradation.
• 135° Split Point Geometry — Aggressive split-point design reduces thrust force by up to 50% and eliminates "walking" on curved or irregular surfaces.
• Ground Flute Finish — Precision-ground flutes with polished surface enhance chip flow and reduce heat buildup in the cutting zone.
• Heavy-Duty Construction — Thicker web design and reinforced core provide additional rigidity for demanding drilling applications.

Applications

Drilling stainless steel (304, 316, 321), heat-resistant superalloys (Inconel, Hastelloy, Waspaloy), hardened steels up to 35 HRC, cast iron, and difficult-to-machine alloys. Essential for aerospace component manufacturing, petrochemical equipment fabrication, marine engine repair, and specialty metalworking shops.

Specifications