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Best Cobalt Drill Bit Sets: Drill Through Hard Metals Faster

Drill smarter, not harder, with these top cobalt drill bit sets

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BY Nikola Petrovski , Trey Williams / LAST UPDATED ON September 14, 2021

While standard HSS (high-speed steel) drill bits are great for wood and soft metal, they literally won’t cut it when it comes to stainless steel and other heat-hardened metals. Cobalt drill bits are constructed out of stronger materials and are more durable and resistant to heat than average bits. They’re the perfect choice if you’re working with stainless steel. Check out our top picks for the best cobalt drill bit sets.

Best Overall
Irwin 29-piece Drill Bit Set, M35 Cobalt Steel
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Summary
Summary

Heavy-duty drill bits constructed from industrial grade steel with five percent cobalt for improved resistance to heat and abrasion and web design for maximum strength and durability. Come in a range of sizes between 1/16 and 1/2 inch.

Pros
Pros

Bits include 135-degree split point tips to eliminate walk and enable immediate drilling. Carry case includes rubber over-molding for increased protection against drops and damage.

Cons
Cons

Some of the bit sizes are inaccurate and slightly smaller than listed. The latching system on the carry case is difficult and awkward to open.

Best Overall
Irwin 29-piece Drill Bit Set, M35 Cobalt Steel
Best Value
Bosch Cobalt M42 Drill Bit Set
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Summary
Summary

High heat-resistant drill bits with eight percent cobalt alloy and surface-hardened, no-skate tips for maximum performance and durability. Available in a wide range of individual sizes and 14- or 21-piece mixed drill bit sets in a handy carry case.

Pros
Pros

Drill bits include a thick web-helix design for extra stability during, particularly tough usage. Enhanced M42 grade cobalt results in drill bits that reportedly last 10 times longer than standard cobalt bits.

Cons
Cons

Indexing on carrying case is difficult to read. The product is slightly more expensive than some of its rivals.

Best Value
Bosch Cobalt M42 Drill Bit Set
Honorable Mention
DeWalt 14-piece Cobalt Pilot Point Drill Bit Set
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Summary
Summary

Set of 14 industrial-strength cobalt steel drill bits in a range of commonly used sizes from 1/16 to 3/8 inch. Specifically designed for use with hard metals, these bits include pilot point tips for accurate drilling, clean holes, and a reduction in locking up after breakthrough.

Pros
Pros

Packaged in the heavy-duty case with interlocking hinge for guaranteed protection and labeled bit slots for ease of use and organization. The set includes a replacement for each of the three most common drill bit sizes.

Cons
Cons

Only available in one set size. Some users describe performance of drill bits as aggressive and grabby.

Honorable Mention
DeWalt 14-piece Cobalt Pilot Point Drill Bit Set

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Our reviews are driven by a combination of hands-on testing, expert input, “wisdom of the crowd” assessments from actual buyers, and our own expertise. We always aim to offer genuine, accurate guides to help you find the best picks.

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Best Overall
Irwin 29-piece Drill Bit Set, M35 Cobalt Steel

If you’re looking for a set of bits that can make your next auto repair project easier, consider adding the Irwin 29-piece Drill Bit Set, M35 Cobalt Steel to your tool kit. Featuring a spiral flute, these precisely-machined bits give you accurate and powerful results. Made out of cobalt-fortified steel materials, these drill bits are capable of withstanding a fair amount of heat. In fact, the metal includes a full five percent of cobalt, bracing the tools to retain their structural integrity despite abrasion and temperature. Ranging in size from 1/16 inch to 1/2 inch, this set comes with all the bits you are most likely to need. With a 135-degree split, they avoid travel during the drilling process, making work both easier and more efficient overall. 


It’s worth noting that since the incremental increases are only 1/64-inches, there can be some issues with the sizing of the individual bits. Some may be nominally smaller than suggested, giving you the risk of increasing walk and compromising the force exerted.

Best Value
Bosch Cobalt M42 Drill Bit Set

Want a set of high-grade drill bits that won’t lead to you going over budget? Take a look at the Bosch Cobalt M42 Drill Bit Set for its reasonable price point and quality construction. The drill bits themself feature a spiral flute and a three-flat shank type. Compatible with most repair projects, the set comes with 21 pieces. By incorporating a substantial amount of cobalt (eight percent), these steel-alloy drill bits are very powerful. The addition of extra cobalt enhances the sturdiness of the bits themselves, helping the parts prevent wear due to friction during use. They use a web-helix design to facilitate stability during work. It prevents the risk of walking and makes it easier to focus the energy of the drill itself. Effective at handling everything from titanium to iron, these affordable bits are a great way addition to any tool kit. 


Keep in mind that, while the individual bits are well sized, the case can be a bit tricky to read. However, once you’re familiar with the drill bit set, the markings aren’t as necessary and this is no longer a concern. 

Most Durable
DEWALT 14-Piece Cobalt Pilot Point Drill Bit Set  

If you're planning to tackle a maintenance project and need a set of bits that can keep up with the demand, check out the DeWalt 14-Piece Cobalt Pilot Point Drill Bit Set. It has a great balance between strength and function. The bits range in size from 1/16-inch to 3/8-inch, which makes the set ideal for all types of projects. All of the pieces come encased in a strong polymer container that makes it easy to store the bits and keep them organized. The ABS material won’t crack nor will it let moisture get close to the bits, preventing the risk of rust and corrosion. Made of cobalt-heavy steel, these precisely constructed bits use a spiral flute to give efficient results. Ideal for compact storage and versatile performance, this bit set is a truly worthy candidate.


Even though the tough construction of the bits is really desirable, they are fairly heavy. Keep this in mind when handling the drill at first to avoid any issues with the bits traveling while you’re using the drill. 

Most Portable
Drill America 29-Piece Cobalt Drill Bit Set

If your garage is overflowing with tools and you want a set of bits that will work well and not take up a ton of space, try the Drill America 29-piece Cobalt Drill Bit Set. It has a unique storage mechanism and sturdy design. Despite coming complete with a large supply of drill bits, ranging from 1/16 inch to 1/2-inch, the set fits just about anywhere. It comes in a round container with individual slots (each clearly marked) for the different bits. The parts themselves feature a spiral flute and a 135-degree point. Split for efficient penetration of hard metals, these bits operate powerfully and precisely. Since the pieces increase in size by 1/64-inches, it’s no issue finding compatible parts. Complete with gold plating, these cobalt-heavy drill bits are able to retain their strength at high speeds, making them ideal for automotive work. 


Keep in mind that, while the bits are sturdy, the case can’t hold up to the same standards. If it falls, the case is likely to get cracked, so keep this in mind when choosing where to store your new bit set. 

Honorable Mention
Stroton Store Metric Cobalt Drill Bits

If you're focused on finding a set of tools that will work over the long term, the Stroton Store Metric Cobalt Drill Bits live up to even the most demanding standards. Made out of cobalt-heavy steel, the metal includes eight percent of this powerful element, ensuring full structural integrity. Falling between 68 and 70 on the Rockwell Hardness Scale, these bits aren’t prone to chipping. They also won’t lose the effectiveness of the split point tip due to ongoing use. Designed to quickly slice through all types of metals including galvanized steel, these bits are ideally suited to automotive work. The bits aren’t prone to travel during work, letting you focus on precision tasks with more ease. Coming with 19 pieces, these bits range in size from 3/64-inch to 1/2-inch bits, this set is complete with a bit for any project you may need to tackle. 


One downside is that the markings are in metric, so if you aren’t familiar with that system, it may require an extra step to convert the digits. In terms of construction quality, however, these bits definitely earn this honorable mention. 

Tips

  • Extend the life of your cobalt drill bits by sharpening them after they become dull, but keep in mind you won’t be able to replicate a pilot point tip when doing so.
  • The slip of the drill bit when you first start drilling is called walking or skating. Choose drill bits with split point or pilot point tips to minimize this if accuracy is important.
  • Make sure you know what you’ll be using the drill bits for before choosing a set, so you can be sure you choose one with the right sizes.

FAQs

Q: What is the difference between M35 and M42 cobalt steel?

A: M35 and M42 refer to the percentage of cobalt in the cobalt steel alloy. M35 is five percent cobalt whereas M42 has eight percent.

Q: Which is better: a cobalt or titanium drill bit?

A: Cobalt steel drill bits are ideal for use with hard metals, like cast iron or stainless steel, because they can be sharpened and have high heat resistance. Titanium bits cannot be sharpened but are equally hard and have anti-corrosive properties so they may provide superior performance with wood and softer metals.

Q: Do I need to use cutting oil with cobalt drill bits?

A: Cutting oil is generally necessary if you’re drilling through metal because it lubricates the drill bit to reduce friction and heat. It’s not necessary if you’re drilling other materials but is certainly a good idea when drilling hard metals in order to improve the lifespan of your drill bits.

Final Thoughts

Constructed in industrial-strength steel with five percent cobalt, the Irwin 29-piece Drill Bit Set, M35 Cobalt Steel is our top pick overall, while the Bosch Cobalt M42 Drill Bit Set is our best value set.