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Drilling through hardened steel isn’t for the faint of heart—or the weak of tools. Unlike softer metals or wood, hardened steel demands extreme toughness, heat resistance, and precision from your drill bits. That’s where carbide and cobalt-tipped drill bits come into play. These specially engineered tools are capable of slicing through the toughest metals without dulling or breaking under pressure.
In this guide, we’ll explore the best carbide drill bits for hardened steel, help you understand what makes them superior, and show you exactly what to look for when making a purchase.
Before buying, consider the following:
No. Regular HSS bits will dull quickly or even snap. For hardened steel, use carbide-tipped or cobalt bits only.
Cobalt bits are made of steel alloyed with cobalt (usually M35 or M42) and are durable for repetitive drilling.
Carbide bits are harder and more brittle—ideal for extremely hard materials but require a steady hand and proper drilling speed.
Use a lubricant like cutting oil, apply steady pressure, and drill at a slow speed. Overheating can damage both the bit and the material.
Yes, but a corded drill or a drill press is better for control and consistent torque. Hand drills can work, but it’s harder to maintain proper pressure and alignment.
Most carbide-tipped bits are not sharpenable without special tools. It’s more common to replace them once dull, unlike cobalt bits which can be resharpened.
When drilling hardened steel, quality matters. The right carbide or cobalt drill bit can save time, money, and frustration. Whether you’re a professional machinist or a home DIYer, the sets from BOSCH, Yougfin, and TITGGI provide a range of options—from premium to budget-friendly.
If you’re after long-term performance and durability, go with the BOSCH CO14B. For variety and value, the Yougfin 29-piece set is a smart choice. And if you need something versatile for multiple materials, the TITGGI set delivers decent performance at a low cost.