RICHELIEU 492261 17-piece cobalt drill bit set

17-piece cobalt Tri-Bore set

The RICHELIEU 492261 set contains 17 cobalt drill bits manufactured from M35 steel with 5% cobalt for high strength and heat resistance. A third cutting edge on bits 1/8 in (3 mm) and larger increases cutting surface area for 17% faster cutting. This design reduces heat buildup and extends service life up to three times longer than standard cobalt bits. The bits suit demanding drilling in ferrous and nonferrous metals including stainless steel.

Capacity and headroom

Thirteen bits from 1/8 in (3 mm) up feature 135° split-point tips for precise starts and reduced walking. Bits 3/16 in (4.76 mm) and larger add three shank flats for secure chuck grip. Fully ground manufacturing ensures straighter holes, while a thicker core adds rigidity for heavy use. The set covers a broad range of common metalworking diameters for professional and serious DIY tasks.

Practical limits of the standard

Bits below 1/8 in (3 mm) lack the third cutting edge and split-point geometry, so they cut slower and require more care to start accurately. The 135° split point is optimised for metal; it is less effective in wood or plastic where a brad point would perform better. Cobalt steel excels in heat resistance but is more brittle than high-speed steel, so excessive side load or misalignment can cause breakage. California Proposition 65 warnings apply for cancer and reproductive harm.