Best Cobalt Drill Bits of 2020

Categories Drills
Cobalt drill bits are the best for drilling hardened metal.

When it comes to drill bits, they don’t come much tougher than cobalt drill bits. If you are drilling holes in iron, steel and even titanium, you need the best cobalt drill bits to get the job done.

We show you 5 of the best cobalt drill bits to give you the lowdown and make choosing the right one a breeze.

What are Cobalt Drill Bits?

Cobalt drill bits are constructed from a steel alloy that contains at least 5 to 8 percent cobalt. Cobalt drill bits are graded as M35 or M42 and denote the quantity of cobalt used in their manufacture. M35 refers to 5 percent cobalt, while M42 has the highest cobalt mix, at 8 percent.

Cobalt is heat resistant and adds superior strength to the bit, making it the ideal tool to drill through iron, steel and even titanium.

With strength also comes weakness. Cobalt drill bits are incredibly brittle and prone to snapping. The length of the bit makes a marked difference in how the drill bit performs under pressure. A longer shaft is more breakable, whereas a shorter length helps the bit retain its core strength.

Types of Cobalt Drill Bits

Essentially, there are 4 types of cobalt drill bits available.

Twist Bit

Twist bits are, by far, the most commonly available and the most preferred. They come in a variety of sizes and are excellent for tackling a multitude of different surfaces. Some come with coatings of gold or bronze-oxide to increase their durability and heat resistance.

This makes them the drill bit of choice for general-purpose use. If you want a drill bit for different applications, this is the one to choose.

Step Bit

Stepped bits are conical in shape, and do exactly what they say on the tin. Their stepped shape provides a whole host of different sizes, all with one drill bit. Typically, they penetrate up to 0.25 inches into the material, and they are also effective when drilling holes in wood.


Countersink drill bits are typically used for drilling into wooden surfaces. They are also useful in drilling through metal because they drill a beveled hole that allows for screws and fasteners to sit flush with the surface of the material. It achieves this conical hole thanks to the design of the tip.


Counterbore drill bits are effective at making bevel holes thanks to their larger, flat surface and small penetrating tip. They are rarely used in metalwork and more commonly found in carpentry for hanging doors, especially in kitchens.

How to Choose the Best Cobalt Drill Bit

What are the factors that decide which cobalt drill bit is the best for you? Let’s find out.


Length matters when it comes to cobalt drill bits. The longer the shaft, the more brittle the bit. Cobalt is notoriously easy to snap when placed under pressure, so by shortening the length of the bit, you are increasing the durability.


If you are buying a set of drill bits, make sure you get a variety of sizes. It increases the practical uses of the set and gives you a more substantial repertoire of drilling options.


The makeup of your drill bit is crucial. The higher the cobalt content, the better your bit will be at withstanding heat and dulling. Also, 8 percent cobalt drill bits have a higher resistance to punishment than 5 percent cobalt drill bits.


The cost is always a valid factor when choosing the drill bits you want. Top-end drill bits will be better quality and last longer, but you should shop to your budget and get the best that you can afford.

The Best Cobalt Drill Bits of 2020

Knowing which cobalt drill bits are the best for you can be tricky. Luckily, we have done a lot of the legwork for you, to bring you our rundown of the 5 best cobalt drill bits.

1. Drill America 29-Piece M35 Cobalt Drill Bit Set

Best Cobalt Drill Bits For Hardened Steel

Drill America - DWD29J-CO-PC 29 Piece M35 Cobalt Drill Bit Set in Round Case (1/16' - 1/2' X 64ths), DWDCO Series
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Drill America has a long history of making tools to a high standard, and this 29-piece cobalt drill bit set is no exception. They have a self-centering 135-degree split point tip to penetrate easier and reduce instances of walking.

It means you can drill smooth and hard material without a pilot hole, and it produces small chips to reduce clogging. Each bit is coated in gold oxide to improve the wear resistance and to help lubricate the bit as it cuts through.

The sizes range from 0.062 inches up to 0.50 inches in 0.016-inch increments. And to keep things neat and organized, the entire set is in a plastic case for handy storage and portability.

  • 135-degree split point tip.
  • Self-centering.
  • Gold oxide coating.
  • 29-piece set.
  • M35 grade.
  • Price.
  • Build quality issues.

Additional Specs

Number of pieces 29
Sizes (inches) 0.063 to 0.50
Tip Split-point
Grade M35
Price $$$

2. DeWALT Cobalt Pilot Point Drill Bit Set

Best Pilot-Point Cobalt Drill Bits

DEWALT Cobalt Drill Bit Set with Pilot Point, 14-Piece (DWA1240)
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DeWALT is another brand that focuses on quality and value. They are a great American success story and are recognized worldwide as leaders in tool making and accessories.

These bits are pilot-point designs, so they are less likely to need a pilot hole drilled. They are also less likely to walk across the surface of the metal. The sizes range from 0.062 inches up to 0.375 inches, so not quite the same scope as the Drill America set but still enough variation to cover most tasks.

This set contains 5 percent cobalt, making them M35 grade, and they are for use on hard metals like stainless steel, angle iron and I-beams.

  • Pilot point design.
  • No need to drill pilot holes.
  • Great price.
  • M35 grade.
  • Limited size range.
  • 5 percent cobalt.
  • Build quality issues.

Additional Specs

Number of pieces 14
Sizes (inches) 0.063 to 0.375
Tip Pilot point
Grade M35
Price $$

3. Bosch 14-Piece Cobalt Metal Drill Bit Set

Best Professional Cobalt Drill Bits

Bosch CO14B 14 Pc. Cobalt M42 Drill Bit Set
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When you think of Bosch you automatically think of German engineering and efficiency. Bosch is one of the leading tool and accessory manufacturers globally and has gained a reputation for quality.

This 14-piece drill bit set comes in sizes ranging from 0.063 inches to 0.50 inches, so whatever the task, this set should cope. Bosch has engineered these cobalt drill bits for the professional market.

What makes this set the ideal choice for contractors and pros is they have been designed with a split-point tip for no skate starts. Right from the get-go, you make accurate holes without slippage.

These bits can also tackle lighter duties like wood, plastic and light gauge metals, making them a great all-rounder.

  • 14-piece set.
  • Engineered for professionals.
  • Split-point tip.
  • Bosch quality.
  • M42 grade.
  • Expensive.
  • Prone to snapping.

Additional Specs

Number of pieces 14
Sizes (inches) 0.063 to 0.50
Tip Split-point
Grade M42
Price $$

4. Irwin Tools M35 Cobalt Drill Bit Set

Best Heavy-Duty Cobalt Drill Bits

IRWIN Drill Bit Set, M35 Cobalt Steel, 29-Piece (3018002)
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This is a 29-piece M35 grade cobalt drill bit set. The sizes start at 0.062 inches and scale up to 0.50 inches. Each bit has a split point 135-degree tip to increase accuracy and reduce wandering across the surface of the metal.

These drill bits contain 5 percent cobalt and are for heavy-duty applications like drilling through stainless steel, cast iron and titanium. They come in a professional-grade storage case lined in rubber and with removable cartridges to make it easier to transport your bits to your worksite.

So far, so good? The only downside is the cost. This set costs almost four times the price of the DeWALT set. At this price tag, these cobalt drill bits are likely to appeal to the professionals.

  • M35 grade.
  • Heavy-duty applications.
  • 29-piece set.
  • 135-degree tip.
  • Professional carry-case.
  • Price.

Additional Specs

Number of pieces 29
Sizes (inches) 0.063 to 0.50
Tip Split-point
Grade M35
Price $$$

5. Comoware Cobalt Drill bit Set

Best Budget Cobalt Drill Bit Set

COMOWARE Cobalt Drill Bit Set- 13Pcs M35 High Speed Steel Twist Jobber Length for Hardened Metal, Stainless Steel, Cast Iron and Wood Plastic with Metal Indexed Storage Case, 1/16'-1/4'
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If value for money is your number one priority, this Comoware drill bit set is hard to beat. This is a 13-piece set, so it lacks the options of the Irwin Tools set, but again, the price is more affordable and costs 6.5 times less.

The sizes range from 0.062 inches to 0.25 inches, highlighting the limitations of the size selections, but at this price, something has to give. The bits are 135-degree split point tips for improved traction, cutting ability, and reduced movement across the surface of the metal.

You even get a carry-case with a size index to make choosing the right attachment easier. All in all, this is a good quality set for not a lot of money. It would be an ideal drill bit set for a beginner.

  • Great price.
  • M35 grade.
  • 13-piece set.
  • Split point tips.
  • Size selection is limited.
  • Bit holder is of poor quality.

Additional Specs

Number of pieces 13
Sizes (inches) 0.063 to 0.25
Tip Split-point
Grade M35
Price $

Cobalt Drill Bit Comparison Chart

Product Best No. of pieces Sizes Tip Grade
Drill America M35 Cobalt Drill Bit Set Hardened Steel 29 0.063 to 0.50″ Split-point M35
DeWALT Cobalt Pilot Point Drill Bit Set Pilot-Point 14 0.063 to 0.375″ Pilot point M35
Bosch Cobalt Metal Drill Bit Set Professional 14 0.063 to 0.50″ Split-point M42
Irwin Tools M35 Cobalt Drill Bit Set Heavy-Duty 29 0.063 to 0.50″ Split-point M35
Comoware Cobalt Drill bit Set Budget Pick 13 0.063 to 0.25″ Split-point M35
Jump to the Full Cobalt Drill Bit Reviews


Can Cobalt Drill Bits Be Sharpened?

Yes, they can. The best tool to use when sharpening a drill bit is a bench grinder. Thanks to the durability of cobalt drill bits, they can be sharpened and reused numerous times.

Are Cobalt Drill Bits Better Than High-Speed Steel (HSS) Bits?

Cobalt drill bits are better at coping with high temperatures and extreme heat. For this reason, they can run for longer without the fear of them dulling and also without the need for them to cool down between tasks.

With a HSS bit, you run the risk of the heat dulling the cutting edge, which means using a lubricant or cooling the bit between jobs to preserve its integrity.

Are Cobalt Drill Bits Better Than Titanium?

They cater to different tasks. Titanium drill bits are better for general-purpose use, whereas cobalt drill bits drill hardened surfaces better. Titanium bits will last 6 or even 10 times longer than HSS bits, while cobalt drill bits are highly resistant to heat and can chew through steel, iron and other smooth metals.

The Bit at the End

If you have an upcoming project that involves drilling through hardened steel or any other smooth and robust material, you should focus your attention on cobalt drill bits.

They love chewing through metals, no matter what the grade, and because they contain cobalt, they are heat resistant and dull slowly, making them long-lasting and excellent value for money.

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About the Author

Mark Weir

Mark spent 24 years working in real estate, so he knows his way around a home. He also worked with contractors and experts, advising them on issues of planning, investments, and renovations. Mark is no stranger to hands-on experience, having renovated his own home and many properties for resale. He likes nothing better than seeing a project through to completion.
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