Olympia Tools 13 Pcs M35 Cobalt Drill Bit Set 1/16-1/4 135° 5471MGJB5454

13-Piece M35 Cobalt Drill Bit Set

This 13-piece set uses M35 cobalt alloy steel with 5% cobalt content for high hardness and heat resistance. Sizes range from 1/16 inch to 1/4 inch to cover common drilling tasks. The 135-degree split tip centres itself on contact and reduces bit wander. A moulded storage case keeps each bit labelled and accessible.

Practical limits of cobalt alloy bits

Cobalt steel resists heat better than standard high-speed steel but remains brittle under side loads. The 135-degree point works well on stainless steel, cast iron, copper and aluminium. Plastics and wood can be drilled, though aggressive flutes may grab thin sheet stock. The set stops at 1/4 inch, so larger holes require different tooling.

Installation and common issues

Bits fit any standard drill chuck that accepts 1/4-inch shanks. Secure the workpiece to prevent the bit from walking despite the self-centring tip. Use cutting fluid on hard metals to manage temperature and extend edge life. Avoid excessive feed pressure, which can snap the brittle cobalt body. Replace bits once the split tip rounds over.