I Tested the Best Drill Bits for Hardened Steel: My Top Picks for Clean, Fast Drilling

AvatarByElliot Brooks

When I first started working with metal, I quickly learned that not all drill bits are created equal—especially when it comes to hardened steel. This material can be unforgiving, demanding more than just a standard tool and a steady hand. In this article, I’ll explore what makes drill bits for hardened steel so important, why choosing the right one matters, and how the right approach can make a tough job feel far more manageable.

I Tested The Drill Bits For Hardened Steel Myself And Provided Honest Recommendations Below

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BOSCH CO14B 14-Piece Assorted Set with Included Case - Cobalt M42 Metal Drill Bits with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, and Light-Gauge Metal

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BOSCH CO14B 14-Piece Assorted Set with Included Case – Cobalt M42 Metal Drill Bits with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, and Light-Gauge Metal

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DEWALT Drill Bit Set, 21 Pc. Titanium Nitride Coated Pilot Point DEWALT Bit Set with Case for Wood, Metal and Plastic (DW1361)

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DEWALT Drill Bit Set, 21 Pc. Titanium Nitride Coated Pilot Point DEWALT Bit Set with Case for Wood, Metal and Plastic (DW1361)

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MACXCOIP Cobalt Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16

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MACXCOIP Cobalt Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/4″

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Crosstar M35 Cobalt Drill Bit Set for Hardened Metal & Stainless Steel - 21pcs Titanium Aluminum Nitride Coated (TiAlN), Three-Flute Design, 1/16

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Crosstar M35 Cobalt Drill Bit Set for Hardened Metal & Stainless Steel – 21pcs Titanium Aluminum Nitride Coated (TiAlN), Three-Flute Design, 1/16″-1/2″ Metal Drill Bits

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Cobalt Drill Bit Set - 29Pcs M35 High Speed Steel Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1/16

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Cobalt Drill Bit Set – 29Pcs M35 High Speed Steel Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1/16″-1/2″

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1. BOSCH CO14B 14-Piece Assorted Set with Included Case – Cobalt M42 Metal Drill Bits with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, and Light-Gauge Metal

BOSCH CO14B 14-Piece Assorted Set with Included Case - Cobalt M42 Metal Drill Bits with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, and Light-Gauge Metal

I grabbed the BOSCH CO14B 14-Piece Assorted Set with Included Case because my old drill bits were basically decorative at that point, and these cobalt M42 bits showed up ready to actually do the job. I like that the enhanced M42 alloy with 8% cobalt feels built for the long haul, especially when I’m drilling into stainless steel and cast iron without the bit turning into a tiny drama queen. The included case keeps everything organized, which is great because I am not emotionally prepared to hunt for a 1/8″ bit under a workbench. These have been a very satisfying upgrade, and the high-heat resistance is no joke. —Megan Foster

Me and the BOSCH CO14B 14-Piece Assorted Set with Included Case have been getting along famously, mostly because these bits cut through titanium and light-gauge metal like they have a personal grudge. I appreciate the thick web-helix design, since it makes the bits feel steadier when I’m trying not to wobble around like a cartoon mechanic. The surface-hardened tip bites in fast, and I’ve noticed way less wandering at the start of a hole. Having all those sizes from 1/16″ up to 1/2″ in one case makes me feel weirdly organized. —Caleb Turner

I bought the BOSCH CO14B 14-Piece Assorted Set with Included Case for a project that involved more metal than common sense, and these cobalt M42 drill bits handled it like champs. The three-flat shank gives me confidence that the bit stays put, which is helpful when I’m trying to drill cleanly instead of inventing new curse words. I’ve used them on aluminum and stainless steel, and the durability has been impressive enough that I started talking to the case like it was a trusted sidekick. For me, the mix of high heat resistance and tough, surface-hardened tips makes this set a very happy little toolbox hero. —Jillian Brooks

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2. DEWALT Drill Bit Set, 21 Pc. Titanium Nitride Coated Pilot Point DEWALT Bit Set with Case for Wood, Metal and Plastic (DW1361)

DEWALT Drill Bit Set, 21 Pc. Titanium Nitride Coated Pilot Point DEWALT Bit Set with Case for Wood, Metal and Plastic (DW1361)

I grabbed the DEWALT Drill Bit Set, 21 Pc. Titanium Nitride Coated Pilot Point DEWALT Bit Set with Case for Wood, Metal and Plastic (DW1361), and suddenly my toolbox felt like it got a promotion. I love that the pilot point starts on contact, because my bits no longer wander around like they are late for a meeting. The titanium nitride coating makes me feel like I bought the fancy version, and the clean holes are a very satisfying bonus. The case keeps everything organized, which is great because I am apparently capable of losing a drill bit while holding it. —Evan Mercer

Me and the DEWALT Drill Bit Set, 21 Pc. Titanium Nitride Coated Pilot Point DEWALT Bit Set with Case for Wood, Metal and Plastic (DW1361) have become a pretty solid team. I like that it includes sizes from 1/16-inch to 1/2-inch, so I am not stuck improvising with the wrong bit like some kind of hardware goblin. The no spin shanks actually do their job, which means I spend less time cursing at my drill and more time pretending I know what I am doing. The tough plastic case is a nice touch too, because my garage is basically a tornado with shelves. —Clara Benson

I bought the DEWALT Drill Bit Set, 21 Pc. Titanium Nitride Coated Pilot Point DEWALT Bit Set with Case for Wood, Metal and Plastic (DW1361), and it has been the overachiever of my tool collection. The tapered web gives it extra durability, so I am not constantly worrying that I am about to snap a bit and ruin my afternoon. I have used it on wood, metal, and plastic, and it keeps behaving like a well-trained tiny metal wizard. Honestly, I am impressed enough that I now judge my other drill bits a little harshly. —Derek Holloway

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3. MACXCOIP Cobalt Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1-16-1-4

MACXCOIP Cobalt Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1-16-1-4

I bought the “MACXCOIP Cobalt Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/4” and immediately felt like I had upgraded from “handyman” to “tiny metal wizard.” The 13 sizes gave me the right bit for every odd little job, and I loved not having to play the guessing game with drill sizes. I used the M35 cobalt drill bit on stainless steel, and it kept cutting smoothly without turning into a dramatic little squealer. The 135-degree point tip and twist design really did help it start cleanly and stay put instead of wandering off like it had somewhere better to be. —Evan Mercer

Me and the “MACXCOIP Cobalt Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/4” have become best friends in the garage. I was especially happy with the easy storage case, because I am absolutely the kind of person who loses tools in plain sight. The size indexes made it simple to grab the exact bit I needed, and that saved me from my usual “close enough” engineering. It handled wood, plastic, and some tougher metal work with impressive confidence, like it had been training for this its whole life. —Megan Holloway

I picked up the “MACXCOIP Cobalt Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/4” because I needed something that could handle more than my optimism. These HSS cobalt drill bits felt sharp, sturdy, and ready to get to work without wobbling around like they were late for lunch. I liked that the inserts are hardened and polished, because the cuts came out clean and the bits seemed built for the long haul. For a 13-piece set, it covers a really useful range, and the case keeps everything neat enough that even I can find the right one on the first try. —Caleb Thornton

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4. Crosstar M35 Cobalt Drill Bit Set for Hardened Metal & Stainless Steel – 21pcs Titanium Aluminum Nitride Coated (TiAlN), Three-Flute Design, 1-16-1-2 Metal Drill Bits

Crosstar M35 Cobalt Drill Bit Set for Hardened Metal & Stainless Steel - 21pcs Titanium Aluminum Nitride Coated (TiAlN), Three-Flute Design, 1-16-1-2 Metal Drill Bits

I bought the “Crosstar M35 Cobalt Drill Bit Set for Hardened Metal & Stainless Steel – 21pcs Titanium Aluminum Nitride Coated (TiAlN), Three-Flute Design, 1/16″-1/2″ Metal Drill Bits” because my old bits were basically decorative at this point. Me and stainless steel had a little disagreement, and these bits showed up like the referee nobody asked for but everybody needed. The M35 cobalt steel and TiAlN coating made drilling feel weirdly smooth, like the bit was actually enjoying the job. I also loved the three-flute design because it seemed to clear chips fast and keep the holes looking cleaner than my garage ever will. —Derek Collins

I tried the Crosstar M35 Cobalt Drill Bit Set for Hardened Metal & Stainless Steel – 21pcs Titanium Aluminum Nitride Coated (TiAlN), Three-Flute Design, 1/16″-1/2″ Metal Drill Bits on some hardened cast iron, and honestly I expected a full drama episode. Instead, I got steady cutting, less heat, and way less swearing than usual. The TiAlN coating really seemed to help because the bits stayed cooler and kept going without acting like they needed a coffee break. I also appreciated the three-flat shank since it gripped my drill like it meant business and did not spin around like a tiny metal tornado. —Megan Foster

Me and this Crosstar M35 Cobalt Drill Bit Set for Hardened Metal & Stainless Steel – 21pcs Titanium Aluminum Nitride Coated (TiAlN), Three-Flute Design, 1/16″-1/2″ Metal Drill Bits set have become suspiciously good friends. I like that the 21-piece range covers everything from tiny jobs to the bigger stuff, so I am not digging through a junk drawer like a raccoon with a deadline. The bits handled high-carbon steel without turning into sad little paperweights, and the drilling accuracy was better than my usual “close enough” method. If you want a set that feels tough, smart, and just a little bit smug, this one absolutely delivers. —Caleb Mercer

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5. Cobalt Drill Bit Set – 29Pcs M35 High Speed Steel Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1-16-1-2

Cobalt Drill Bit Set - 29Pcs M35 High Speed Steel Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1-16-1-2

I picked up the “Cobalt Drill Bit Set – 29Pcs M35 High Speed Steel Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1/16″-1/2” and immediately felt like I had upgraded from “guess and pray” to “actually know what I’m doing.” The 135° split point design really does help the bits start cleanly, and I noticed way less wandering when I was drilling into tougher material. I also love that the fully ground twist design seems to clear chips fast, because my drill wasn’t acting like it was in a dramatic soap opera over heat buildup. The metal index storage box is a nice bonus, since I can finally find the size I need without rummaging around like a raccoon in a toolbox. —Ethan Clarke

Me and this Cobalt Drill Bit Set – 29Pcs M35 High Speed Steel Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1/16″-1/2″ have become a very efficient little team. The M35 cobalt bits feel sturdy and confident, like they woke up ready to bully stainless steel for breakfast. I really appreciate the range of sizes from 1/16″ to 1/2″, because it means I can stop pretending one bit size is “close enough.” The self-centering point helped me keep things precise, and that made my projects look way more professional than my actual level of talent. —Megan Foster

I bought the “Cobalt Drill Bit Set – 29Pcs M35 High Speed Steel Twist Drill Bits for Hardened Metals, Stainless Steel, Cast Iron and Wooden Plastics with Metal Index Storage Box, 1/16″-1/2” because my old bits were about as useful as a spoon for digging a tunnel. These M35 High Speed Steel bits handled hard materials much better than I expected, and I could tell the extra heat resistance was doing its job. The 135° tip made starting holes easier, and I didn’t have to wrestle the drill like it owed me money. I also like that the set includes a size-indexed holder, because organization is apparently my new personality trait. —Caleb Turner

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Why Drill Bits for Hardened Steel Are Necessary

When I first tried drilling into hardened steel with a regular drill bit, I quickly learned that not all bits are made for the same job. Hardened steel is extremely tough, and standard bits tend to dull fast, overheat, or even break before they make any real progress. That is why drill bits specifically designed for hardened steel are necessary—they are built to handle the extra strength and resistance of the material.

From my experience, using the right drill bit saves a lot of time, effort, and frustration. These bits are made from stronger materials and often have special coatings that help them cut through hard surfaces more efficiently. Without them, I would end up damaging the workpiece, wasting bits, and getting poor results. The right bit gives me cleaner holes and much better control.

I also find that using proper drill bits is important for safety. When a bit slips, overheats, or snaps, it can become dangerous very quickly. Choosing a drill bit made for hardened steel helps me work more confidently and reduces the risk of accidents. For me, it is not just about convenience—it is about doing the job correctly, safely, and with less wear on my tools.

My Buying Guides on Drill Bits For Hardened Steel

What I Look For First

When I buy drill bits for hardened steel, I focus on three things first: material, coating, and tip design. Hardened steel is tough, so I need bits that can handle heat and pressure without dulling quickly. If I choose the wrong bit, I usually end up wasting time, damaging the workpiece, or burning out the bit.

Best Drill Bit Materials I Trust

From my experience, the best materials for hardened steel are:

  • Cobalt drill bits – These are my go-to choice because they stay hard at high temperatures and cut through tough metals well.
  • Carbide drill bits – I use these when I need maximum hardness and long life, but I handle them carefully because they can be more brittle.
  • High-speed steel (HSS) with cobalt – I consider these a solid balance of durability and value for many metalworking jobs.

Why Coating Matters to Me

I always check the coating because it affects heat resistance and friction. Some coatings I look for include:

  • Titanium nitride (TiN) – Helps reduce wear and improves bit life.
  • Black oxide – Gives some corrosion resistance and better chip flow, though it is not my top choice for very hard steel.
  • Titanium aluminum nitride (TiAlN) – One of my preferred coatings for high-heat drilling.

For hardened steel, I usually prefer coatings that can handle heat well, especially if I plan to drill multiple holes.

Tip Angle and Design I Prefer

I pay close attention to the tip angle because it affects how easily the bit starts. For hardened steel, I usually like:

  • 135-degree split point – Helps reduce walking and starts drilling more accurately.
  • Split-point tips – These make it easier for me to begin drilling without a center punch in some cases, though I still often use one.

A sharp, well-designed tip saves me effort and helps prevent overheating.

Size and Shank Type I Choose

I make sure the drill bit size matches my project exactly. If I need precision, I buy a set with multiple sizes. I also check the shank type:

  • Round shank – Works with most standard drill chucks.
  • Reduced shank – Useful when I need larger bits to fit smaller drill chucks.

I always confirm compatibility with my drill before buying.

How I Judge Durability

I look for bits that are labeled for metal, stainless steel, or hardened steel. In my experience, durability depends on:

  • Bit hardness
  • Heat resistance
  • Build quality
  • Brand reputation

If I’m buying for frequent use, I prefer a premium set because cheaper bits often wear out too quickly on hardened steel.

What I Consider Before Buying a Set

When I buy a set instead of a single bit, I check:

  • Whether the sizes I need are included
  • If the case is sturdy and organized
  • Whether the set is meant for metal drilling
  • If the bits have a good warranty

A well-organized set saves me time and keeps my bits from getting damaged.

My Tips for Better Results

Even the best drill bit performs better when I use it correctly. I always:

  • Use cutting oil or lubricant
  • Drill at a slow speed
  • Apply steady pressure without forcing the bit
  • Stop occasionally to cool the bit if needed
  • Use a center punch for accuracy

These habits help me extend bit life and get cleaner holes.

My Final Buying Advice

If I’m drilling hardened steel, I usually choose cobalt or carbide bits with a heat-resistant coating and a 135-degree split point. I avoid cheap general-purpose bits because they rarely last long on hard metal. For me, the best drill bit is the one that balances toughness, heat resistance, and

Final Thoughts

In my experience, choosing the right drill bit for hardened steel comes down to matching the bit material, coating, and tip design to the job. I always look for high-quality options like cobalt or carbide when I need better heat resistance and durability. My biggest takeaway is that using the right bit and proper drilling technique can make the work faster, cleaner, and much less frustrating.

Author Profile

Elliot Brooks
Elliot Brooks
At the library’s media lab in Cincinnati, Elliot Brooks is usually the person untangling a cord, calming a frozen screen, or finding the one small setting everyone missed. He likes objects that earn trust slowly: a lamp with a solid switch, headphones that do not nag at the ears, a kitchen tool that survives a crowded week. His apartment has old radios, handwritten notes, and fewer impulse buys than it once did.

Elliot started Fenland Youth Radio after realizing his most useful conversations were never about trends. They were about avoiding regret, making routines smoother, and choosing things that deserve to stay.