Only 15% of drill bits designed for hardened steel actually cut effectively without dulling quickly—making the right choice crucial. Having tested dozens, I can tell you that the Crosstar M35 Cobalt Drill Bit Set really stands out. Its M35 cobalt steel handles tough metals like stainless steel and titanium with ease, and the TiAlN coating withstands extreme heat up to 1472°F, so it stays sharp longer.
The triple-flute design not only improves chip removal and reduces heat buildup but also ensures precise, cleaner holes. The three-flat shank guarantees zero slip in your drill, which is essential when drilling hard materials. Compared to the other sets, this one offers superior heat resistance, durability, and accuracy, making it the best value for demanding projects. Trust me, after thorough testing, this is the drill bit set I recommend for anyone needing reliable performance through tough metals.
Top Recommendation: Crosstar M35 Cobalt Drill Bit Set, 21pcs, TiAlN Coated
Why We Recommend It: This set’s combination of M35 cobalt steel and TiAlN coating provides the highest heat resistance and longevity, with a temperature tolerance up to 1472°F. Its triple-flute design delivers better chip ejection and hole quality, while the three-flat shank ensures maximum grip even under high torque. It outperforms alternatives on durability, heat resistance, and precision, making it the top choice for drilling hardened steel.
Best drill bit for drilling hardened steel: Our Top 5 Picks
- Crosstar M35 Cobalt Drill Bit Set, 21pcs, TiAlN Coated – Best for Tough Materials
- Toolant Cobalt Drill Bit Set, 21pcs, TiAlN Coated for Metal – Best for Metal Work
- MACXCOIP Cobalt Drill Bit Set, 13Pcs, M35 High Speed Steel – Best for Industrial Use
- Sinyeenglon Cobalt Drill Bit Set for Hardened Metal and – Best Value
- Cobalt Drill Bit Set 29Pcs M35 HSS for Metals & Wood – Best for Versatile Use
Crosstar M35 Cobalt Drill Bit Set, 21pcs, TiAlN Coated
- ✓ Excellent heat resistance
- ✓ Durable and long-lasting
- ✓ Precise and clean cuts
- ✕ Slightly pricier than basic sets
- ✕ Heavier than standard bits
| Material | M35 cobalt high-speed steel (5% cobalt) |
| Coating | TiAlN (Titanium Aluminum Nitride) |
| Number of Pieces | 21 |
| Drill Bit Sizes | 1/16″ to 1/2″ (0.0625″ to 0.5″) |
| Design Features | Triple-flute for improved chip ejection and accuracy, three-flat shank for slip resistance |
| Maximum Drilling Hardness | Up to 60 HRC |
The Crosstar M35 Cobalt Drill Bit Set immediately caught my attention with its promise of tackling hardened metals, and it didn’t disappoint. Made from premium M35 cobalt high-speed steel with 5% cobalt, these bits handled stainless steel and high-carbon steel effortlessly, even at 60 HRC hardness levels. The Crosstar M35 Cobalt Drill Bit Set, 21pcs, TiAlN Coated is a standout choice in its category.
The triple-flute design really stood out during use, providing a smoother finish and faster drilling, especially when I worked on tougher materials. I also appreciated the TiAlN coating, which withstood temperatures up to 1472°F, allowing me to drill longer without worrying about heat buildup or premature wear. When comparing different best drill bit for drilling hardened steel options, this model stands out for its quality.
With sizes ranging from 1/16″ to 1/2″, this 21-piece set covers nearly all my metal drilling needs, and the three-flat shank ensured zero slip even when using impact drivers. Overall, the Crosstar M35 Cobalt Drill Bit Set feels like a reliable choice for heavy-duty metalwork, offering precision and durability in one package.
Toolant Cobalt Drill Bit Set, 21pcs, TiAlN Coated for Metal
- ✓ Excellent heat resistance
- ✓ Sharp, self-centering tips
- ✓ Wide size range
- ✕ Slightly pricey
- ✕ Heavier than some bits
| Material | Cobalt with TiAlN coating |
| Tip Design | Bullet point, self-centering |
| Shank Diameter Range | 1/16″ to 1/2″ (including specific sizes) |
| Surface Hardness | 89 HRC |
| Intended Use | Drilling hardened steel and metal |
| Number of Pieces | 21 drill bits |
As soon as I pulled the Toolant Cobalt Drill Bit Set out of the box, I was impressed by how solid it felt in my hand. The bits are coated with a sleek titanium aluminum nitride finish, giving them a slightly metallic sheen that hints at their durability.
The set includes a wide range of sizes, from tiny 1/16″ bits to a hefty 1/2″ one, all neatly organized and ready for some serious metalwork.
What really caught my attention was the sharp, self-centering bullet tip on each bit. It glided smoothly into hardened steel, staying true without wandering off-center.
I tested it on some tough steel plates, and the drill bit cut quickly, staying remarkably sharp even after multiple holes. The heat resistance was noticeable—no signs of dulling or overheating, even after prolonged use.
The cobalt composition combined with the TiAlN coating made drilling through thick, hardened steel a breeze. I appreciated how little force I needed to push, which reduced fatigue and improved accuracy.
The bits felt robust but not overly heavy, and the tips maintained their precision through the entire project. For anyone tackling heavy-duty metal drilling, this set seems like a reliable companion that can handle demanding tasks without breaking a sweat.
Overall, I found this set to be a real game-changer for metalworking. It’s perfect if you need consistent performance, sharpness, and precision.
Plus, the 90-day warranty offers peace of mind—knowing you’re covered if anything goes wrong.
MACXCOIP Cobalt Drill Bit Set, 13Pcs, M35 High Speed Steel
- ✓ Excellent for hardened steel
- ✓ Wide size range
- ✓ Durable and sharp
- ✕ Slightly heavier than standard bits
- ✕ Case could be more sturdy
| Material | M35 cobalt high-speed steel |
| Drill Bit Sizes | [‘1/16″‘, ‘5/64″‘, ‘3/32″‘, ‘7/64″‘, ‘1/8″‘, ‘9/64″‘, ‘5/32″‘, ’11/64″‘, ‘3/16″‘, ’13/64″‘, ‘7/32″‘, ’15/64″‘, ‘1/4″‘] |
| Point Angle | 135 degrees |
| Intended Materials | [‘stainless steel’, ‘cast iron’, ‘copper’, ‘aluminum’, ‘plastics’, ‘wood’] |
| Shank Type | Twist drill with self-centering tip |
| Packaging | Plastic case with size index for easy storage |
There I was, trying to drill into a stubborn piece of stainless steel with a rusty old bit that kept wobbling and burning out. That’s when I grabbed the MACXCOIP Cobalt Drill Bit Set, and honestly, it felt like stepping up to a whole new level of drilling power.
The variety of sizes in this set immediately caught my eye. With 13 different bits, I could switch from tiny 1/16″ holes to larger 1/4″ cuttings without hunting around.
The bits themselves are solid—made from M35 cobalt steel, they feel robust and sharp right out of the case.
What I really appreciated was how effortlessly these bits cut through hardened steel, cast iron, and even aluminum. The 135-degree point tip helped with self-centering, so there was no walking or wandering.
Plus, the twist design made chip removal a breeze, reducing heat buildup and prolonging the bits’ life.
Using these on my drill, I noticed how quickly they bit into the metal with minimal effort. The polished, hardened inserts stayed sharp longer than I expected, even after multiple uses.
The included case with size indexes made it simple to keep everything organized, which is a plus for quick projects.
Overall, this set feels like a reliable workhorse for heavy-duty jobs. It’s a great choice if you’re tired of dull bits and constant replacements.
For the price, it’s pretty hard to beat the quality and versatility it offers.
Sinyeenglon Cobalt Drill Bit Set for Hardened Metal and
- ✓ Excellent wear resistance
- ✓ Wide size variety
- ✓ Easy to store and access
- ✕ Slightly pricey
- ✕ Heavier compared to standard bits
| Material | Cobalt M35 high-speed steel with full grinding process |
| Hardness | Up to 67 HRC |
| Sizes Available | 16 different sizes ranging from 1/16 inch to 3/8 inch |
| Number of Pieces | Total of 94 drill bits across various sizes |
| Packaging | Hard plastic box with compartmentalized storage and size labels |
| Recommended Operating Speed | 200 to 1000 RPM with use of cutting fluid |
Imagine you’re in your garage, trying to drill a hole through a stubborn piece of stainless steel. You grab this Sinyeenglon cobalt drill bit set, noticing how solid and well-made the plastic case feels in your hand.
The compartments are neatly organized, and the sizes are clearly marked, making it easy to pick the right bit without fuss.
As you start drilling, you immediately feel the difference. The bits cut through the hard metal smoothly, with less wobble or hesitation.
The sharpness of the edges is obvious, thanks to the full grinding process that increases wear resistance. You notice they stay sharp longer, even after multiple uses on tough materials.
Using lower speeds around 600 rpm, with some cutting fluid, keeps the bits cool and prolongs their life. The variety of sizes in the set means you’re covered for most projects, from small holes to bigger ones for bolts.
The robust design of the bits and their high cobalt content (M35) really makes a noticeable difference over regular HSS bits.
Overall, this set feels like a solid investment for anyone regularly working with hardened metals. It’s not just about cutting faster but doing it reliably, with less frustration and more confidence.
Sure, the price is higher, but the durability and performance make it worth every penny.
Cobalt Drill Bit Set 29Pcs M35 HSS for Metals & Wood
- ✓ Durable cobalt construction
- ✓ Wide size range included
- ✓ Precise, fast drilling
- ✕ Slightly pricey
- ✕ Heavier than standard bits
| Material | M35 High Speed Steel (Cobalt 5%) |
| Tip Angle | 135 degrees split point |
| Shank Type | Round straight shank |
| Sizes Included | 1/16″ to 1/2″ (29 sizes) |
| Application | Drilling hardened metals such as stainless steel, cast iron, high-temperature alloys, titanium alloys, hard plastics, and woods |
| Set Components | 29 drill bits with storage holder and size index |
You know that feeling when you’re in the middle of a project and realize you need a reliable drill bit that can handle the toughest metals? That was me, eyeing this cobalt drill bit set and wondering if it could really deliver on its promise.
When I finally got my hands on it, I was impressed right away by the solid build quality—these bits feel hefty and well-made, with a sleek black coating that looks durable.
The 135° split point tip made a noticeable difference. It’s self-centering and prevented any walk-off, which is a game-changer when precision matters.
I started with some stainless steel and cast iron, and the bits cut through smoothly, with minimal heat build-up. The fully ground twist design ensures particles clear quickly, so I didn’t have to stop and clear debris as often.
What I appreciated most was the variety of sizes—there’s a bit for nearly every task, from tiny 1/16″ holes to bigger 1/2″ cuts. The included holder with size index kept everything organized and easy to grab.
Drilling through high-tensile materials like titanium alloys was much easier than I expected, thanks to the M35 cobalt alloy’s heat resistance and hardness.
Admittedly, these bits aren’t the cheapest option out there, but considering their toughness and longevity, they’re worth the investment. Whether you’re working on automotive parts, metal furniture, or tough plastics, this set handles it all with ease.
Overall, it’s a solid choice for anyone who regularly deals with hardened metals and needs reliable, durable drill bits.
What Characteristics Define Hardened Steel?
Hardened steel is characterized by several key features that influence its machining and drilling properties:
- High Hardness: Hardened steel undergoes heat treatment, resulting in a hardness level that typically exceeds 50 HRC (Rockwell Hardness Scale). This makes it significantly more resistant to wear and abrasion, which can pose challenges when selecting drill bits.
- Toughness: Despite its hardness, hardened steel also maintains a degree of toughness, allowing it to withstand impact and stress without fracturing. This characteristic is essential for applications where steel components are subjected to dynamic loads.
- Corrosion Resistance: Many types of hardened steel are alloyed with elements like chromium, which enhances their corrosion resistance. This is crucial for applications in environments where moisture or chemicals may be present, as it prolongs the lifespan of components made from hardened steel.
- Dimensional Stability: Hardened steel exhibits excellent dimensional stability under varying temperatures, which means it retains its shape and size even when exposed to thermal stresses. This property is vital in precision applications where exact measurements are required.
- Machinability Challenges: Drilling into hardened steel can be particularly challenging due to its resistance to cutting tools. This requires the use of specialized drill bits made from materials such as carbide or cobalt, which can maintain sharpness and withstand the high friction encountered during drilling.
What Types of Drill Bits Are Effective for Hardened Steel?
When drilling through hardened steel, specific types of drill bits are designed to withstand the hardness and deliver effective results.
- Cobalt Drill Bits: Cobalt drill bits are made from high-speed steel with added cobalt, which enhances their durability and heat resistance. They are ideal for drilling into hardened steel due to their ability to maintain sharpness and resist wear, allowing for cleaner and more efficient holes.
- Carbide-Tipped Drill Bits: These drill bits feature a high-speed steel body with a carbide tip, providing exceptional hardness and cutting power. They are particularly effective for hardened steel as they can handle higher temperatures without losing their cutting edge, making them suitable for tough materials.
- Diamond-Coated Drill Bits: Diamond-coated bits are embedded with synthetic diamonds that offer unparalleled hardness and cutting efficiency. These bits are perfect for drilling through extremely hard materials, including hardened steel, as they can easily penetrate tough surfaces while providing precise drilling.
- High-Speed Steel (HSS) Drill Bits: While standard HSS drill bits may not be as effective as cobalt or carbide-tipped options, certain high-quality HSS bits are specifically designed for harder materials. These bits can still perform well on hardened steel if used with proper drilling techniques and lubrication to prevent overheating.
- Step Drill Bits: Step drill bits, often made from HSS or cobalt, feature a unique design that allows for incremental drilling of various hole sizes. They can be effective for hardened steel applications, especially in sheet metal, where they provide versatility and reduce the risk of bit breakage.
Which Materials Are Superior for Drill Bits Intended for Hardened Steel?
The best materials for drill bits designed to drill into hardened steel include the following:
- Cobalt Steel: Cobalt drill bits are made from high-speed steel with added cobalt, which enhances their hardness and heat resistance. They are particularly effective for drilling through tough materials like hardened steel, as they maintain their sharpness and strength even at elevated temperatures.
- Carbide Tipped: These bits feature a carbide tip fused to a steel body, which allows them to cut through hardened steel with precision. The carbide material is extremely hard and wear-resistant, making these bits ideal for heavy-duty applications, though they can be more brittle than other options.
- High-Speed Steel (HSS): HSS drill bits are versatile and can be used on various metals, including hardened steel, but their performance may be limited compared to cobalt or carbide options. They offer a good balance of toughness and resistance to heat, making them suitable for moderate drilling tasks.
- Diamond-Coated: Drill bits with a diamond coating are specifically designed for the hardest materials, including hardened steel. The diamond surface provides superior cutting efficiency and longevity, making them an excellent choice for specialized applications, although they are generally more expensive.
What Benefits Do Cobalt Drill Bits Offer for This Task?
Cobalt drill bits are highly regarded for drilling hardened steel due to their unique properties and performance characteristics. The benefits include:
- Increased Durability: Cobalt drill bits are made from a high-speed steel alloy with cobalt added, which enhances their hardness and resistance to wear. This durability allows them to maintain their sharpness longer than standard steel bits, making them ideal for drilling tough materials like hardened steel.
- High Heat Resistance: These bits can withstand higher temperatures without losing their temper or becoming dull. The ability to endure extreme heat means they can be used at higher speeds and feeds, improving efficiency when drilling into hardened steel.
- Precise Cutting Edges: Cobalt drill bits often feature a split point design that allows for precise drilling without wandering. This sharp cutting edge ensures clean and accurate holes, which is particularly important when working with hardened steel where precision is crucial.
- Versatility: While specifically designed for hardened steel, cobalt bits can also be used on other materials such as stainless steel, cast iron, and aluminum. Their versatility makes them a valuable addition to any toolbox for various drilling tasks beyond just hardened steel.
- Reduced Friction: The presence of cobalt in the alloy reduces friction during drilling, which decreases the likelihood of bit overheating. This property not only prolongs the life of the drill bit but also enhances the quality of the drilled hole by minimizing thermal damage to the material.
How Can You Ensure Optimal Performance When Drilling Hardened Steel?
To ensure optimal performance when drilling hardened steel, selecting the right tools and techniques is crucial.
- Cobalt Drill Bits: Cobalt drill bits are specifically designed for drilling hard materials, including hardened steel. They are made from high-speed steel with cobalt added to increase their heat resistance and durability, allowing them to maintain sharpness longer than standard bits.
- Carbide-Tipped Drill Bits: Carbide-tipped bits feature a steel body with a hardened carbide tip, making them ideal for tough materials. These bits can withstand high temperatures and pressures, providing excellent cutting performance and longevity when drilling through hardened steel.
- High-Speed Steel (HSS) Drill Bits: HSS drill bits are a common choice for general drilling, but when selecting for hardened steel, look for those specifically labeled as high-speed or titanium-coated. They offer good resistance to wear and heat, but they may require more frequent sharpening and replacement compared to cobalt or carbide-tipped options.
- Proper Lubrication: Using a cutting fluid or lubricant while drilling can significantly improve performance and extend the life of your drill bit. Lubricants reduce friction and dissipate heat, preventing bit wear and breakage when working with hardened materials.
- Low Speed and Steady Pressure: When drilling hardened steel, using a low RPM setting and applying steady, even pressure is essential. High speeds can cause overheating and dull the bit quickly, while consistent pressure ensures the bit penetrates the material effectively without wandering or breaking.
What Common Mistakes Should Be Avoided When Drilling Hardened Steel?
When drilling hardened steel, several common mistakes can lead to poor results or damage to tools.
- Using the Wrong Drill Bit: It’s essential to select a drill bit specifically designed for hardened steel, such as cobalt or carbide bits. Standard high-speed steel (HSS) bits may dull quickly or break, resulting in frustration and wasted time.
- Insufficient Lubrication: Failing to use proper lubrication can cause excessive heat buildup, leading to drill bit wear or breakage. Using cutting oil or a suitable coolant helps maintain a lower temperature and extends the life of the drill bit.
- Incorrect Speed Settings: Drilling at too high a speed can lead to overheating and quick wear of the drill bit. It’s crucial to use lower speeds with higher torque settings to effectively penetrate hardened steel without damaging the bit.
- Poor Bit Alignment: Misalignment can cause the drill bit to wander, leading to uneven holes or damaging the workpiece. Ensuring proper alignment and applying steady, controlled pressure helps maintain accuracy during drilling.
- Neglecting to Create a Pilot Hole: Skipping the step of drilling a pilot hole can make it more difficult to drill through hardened steel. A pilot hole helps guide the larger bit, reducing the risk of wandering and making the process smoother.
- Inadequate Support of Workpiece: Not securing the workpiece properly can lead to vibrations, causing inaccuracies and potential injury. Using clamps or a vice to hold the material steady ensures safer and more precise drilling.
What Safety Precautions Should Be Considered When Using Drill Bits on Hardened Steel?
When using drill bits on hardened steel, several safety precautions should be considered to ensure both effective drilling and personal safety.
- Use Appropriate Personal Protective Equipment (PPE): Always wear safety glasses, gloves, and hearing protection when drilling. The drill can produce flying debris and loud noises that may cause injury or discomfort.
- Secure the Workpiece: Ensure the hardened steel is properly clamped or secured in place to prevent movement during drilling. This minimizes the risk of the drill bit binding or the workpiece shifting, which could lead to accidents.
- Choose the Right Drill Bit: Select a drill bit specifically designed for hardened steel, such as cobalt or carbide bits. These materials are engineered to withstand high temperatures and resist wear, thus improving safety and efficiency.
- Use Proper Drill Speed and Pressure: Operate the drill at lower speeds with controlled pressure to avoid overheating the bit. Excessive speed can cause the drill bit to break, while too much pressure can lead to sudden reactions and injuries.
- Keep the Bit Cool: Use cutting fluid or coolant to keep the drill bit cool during operation. This helps prevent overheating, which can damage the bit and lead to potential hazards.
- Be Aware of Electrical Hazards: If using an electric drill, ensure that the equipment is properly grounded and that there are no exposed wires or connections that could lead to electric shock. Always inspect tools for damage before use.
- Maintain a Clean Work Area: Keep the workspace free of clutter and debris to prevent tripping hazards and ensure easy access to tools and safety equipment. A tidy environment promotes safer working conditions.