Hardened steel is medium- or high-carbon steel that has been given heat treatment, rapidly cooled and tempered. The high amount of carbon in the steel makes it possible to harden the metal.
Hardened steel is resistant to wear and high-impact pressure, making it a choice material for applications that require hard-wearing materials. These characteristics can also make it challenging to machine hardened steel. Read on to discover the best drill bits for drilling into hardened steel.
Titanium drill bits are one option for drilling hardened steel. These drill bits are high-speed steel bits coated with titanium nitride. High-speed steel bits that consist of vanadium and tungsten can drill through soft steel, but they won’t cut through hardened steel.
The titanium nitride coating has a dark gold appearance, improves wear resistance, and reduces friction. Since the titanium nitride is just a coating, once your drill bit wears down, you cannot resharpen it and maintain its performance level. The titanium layer will no longer be on the drill bit except in the fluting and perhaps on the sides.
Cobalt drill bits are often the best for drilling into hardened steel. Whereas titanium drill bits only have titanium in the coating, cobalt bits have cobalt throughout. After cobalt drill bits get worn out over time, you can resharpen them.
Cobalt drill bits contain an alloy of five to eight percent cobalt. M35 bits contain approximately five percent cobalt, and M42 bits contain about eight percent cobalt.
The more cobalt the bit contains, the harder the metal it can drill through. But the tradeoff is that increasing the cobalt increases the drill bit’s brittleness. Be sure to use the appropriate drilling techniques to preserve your cutting tools.
Carbide is a compound composed of carbon and a metal. Carbide drill bits are tungsten carbide and can contain cobalt for enhanced durability. Carbide drill bits can handle higher temperatures than cobalt drill bits.
These drill bits can be tungsten carbide tipped or full body. Carbide-tipped bits can drill through hard, non-metallic materials like masonry. If you want to drill hardened steel with tungsten carbide, use a full-body bit.
If you’re looking for a tool to cut through hardened steel, check out the cobalt drill bit sets at Drill Bit Warehouse. Our premium M42 drill bits come in various lengths to suit your project needs. Shop with us today for high-performance drill bits.