Drill bits come in various shapes, sizes, and materials. Of the materials you are likely to encounter, nothing is more durable than cobalt, which is why professionals usually choose it for their drilling needs.
A high-quality cobalt drill bit will allow you to make holes in iron, steel, and even titanium, so it will be suitable for any drilling job. However, it is still important to choose carefully to ensure the best possible results.
To help you find the right product for your needs, we have reviewed five of the best cobalt drill bits that are currently available. We chose these bits for their type, size, material, and price.
- 135-degree split point tip
- Self-centering
- Gold oxide coating
- Pilot point design
- No need for pilot holes
- M35 grade
- Engineered for professionals
- Split-point tip
- M42 grade
- For heavy-duty use
- 135-degree tip
- Includes professional carry-case
- 13-piece set
- Split point tips
- M35 grade
What is a Cobalt Drill Bit?
Cobalt drill bits are made of a steel alloy that contains at least 5% to 8% cobalt. These bits are graded as M35 or M42 depending on how much cobalt they contain. M35 refers to 5% cobalt, whereas M42 has the highest cobalt content at 8%.
Cobalt is strong and heat-resistant, so it is ideal for coping with the demands of drilling through iron, steel, and even titanium. Metal becomes blunt far more quickly when it is hot, so preventing it from overheating will make a significant difference to its durability.
This isn’t to say that cobalt drill bits are without flaws. Their cobalt content makes them more brittle, which means they are prone to snapping under pressure. The length of the drill bit has a significant influence on this, with a longer shaft being more breakable, while shorter ones are stronger.
Types of Cobalt Drill Bits
There are four main types of cobalt drill bits to choose from:
Twist Bit
Twist bits are by far the most popular and widely-available type of cobalt drill bits. There are many different sizes and they are suitable for drilling into various materials. Some bits have coatings of gold or bronze oxide that improve their durability and heat resistance.
This all combines to make twist bits the best option for general-purpose use. If you want a drill bit that will be able to tackle the majority of drilling tasks, choose a carbide twist bit.
Step Bit
Stepped bits have conical shapes, with multiple ridges leading to their point. The result of this stepped shape is that a single bit can drill holes of multiple sizes, depending on how far it drills into the material. They typically penetrate up to a quarter-inch into the material and they are also very effective at drilling holes into wood.
Countersink
Countersink drill bits are typically used when drilling into wood. They are also useful for drilling metal because they drill a beveled hole, which means screws and fasteners will sit flush with the surface of the material. This is thanks to their conical design, which will allow you to drill a hole and countersink it at the same time.
Counterbore
Counterbore drill bits are very effective at making bevel holes thanks to their wider, flatter surface and small penetrating tip. They are rarely used in metalwork and are more commonly found in carpentry for tasks such as mounting doors, especially in kitchen units.
How to Choose
Even once you decide to use a cobalt drill bit, you will still have a wide range of different options, which can make it difficult to choose the right one for your needs. However, there are some key points to think about, which should help you make a decision:
Length
You will need to use the right length bit for the job but you also need to pay extra attention to the length when choosing a cobalt drill bit. Cobalt bits are brittle, which makes longer bits more prone to snapping. On the other hand, shorter bits are more durable and you should be able to use one without any concern
Sizes
If you want to buy a set of drill bits, look for as much variety as possible in terms of size. The more sizes a set has, the more versatile it will be and the more options you will have when drilling holes.
Material
You are looking for a cobalt drill bit but there is still a surprising amount of difference in the composition of specific bits. The higher the bit’s cobalt content, the better it will be at enduring heat without dulling. An M42 bit, which contains 8% cobalt, will be more durable than an M35, which contains 5% cobalt.
Price
Budget is an unavoidable part of buying any tool or accessory and this is also true for cobalt bits. If you are buying a cobalt bit, you have already decided to choose a more expensive option than high-speed steel and other basic bits. Even among cobalt bits, top-quality products will cost more, but they should make up for this with improved durability.
Product Reviews
Cobalt drill bits have become the industry leader among professional users, so they are a great option if you are looking for the highest-quality bit possible. To help you find the right piece for your needs, we have reviewed five of the best cobalt drill bits you can buy today. We chose these products for their material, which sizes and types are included, and whether or not they have protective coatings.
Drill America 29-Piece M35 Cobalt Drill Bit Set
Best Cobalt Drill Bits For Hardened Steel
Unsurprisingly given the brand’s name, Drill America specializes in drills and their accessories, and this 29-piece cobalt drill bit set lives up to its high reputation. Its bits have self-centering 135-degree split point tips to help them penetrate more easily and keep the bit from walking during use.
This means you will be able to drill smooth, hard materials without a pilot hole, and the bits release small chips to reduce clogging. Each bit is coated in gold oxide to improve its durability and to lubricate the bit as it works its way through tough materials.
The included sizes range from 0.062 inches up to 0.50 inches in 0.016-inch increments. To keep the bits well-organized, the entire set comes in a plastic case for convenient storage and better portability.
Pros
- 135-degree split point tip
- Self-centering
- Gold oxide coating
- 29-piece set
- M35 grade
Cons
- Expensive
- Possible quality issues
Product Specs
| Number of pieces | 29 |
| Sizes (inches) | 0.063 to 0.50 |
| Tip | Split-point |
| Grade | M35 |
| Price | $$$ |
Our Ratings
DeWALT Cobalt Pilot Point Drill Bit Set
Best Pilot-Point Cobalt Drill Bits
DeWALT is one of the leading tool brands in the world, with an emphasis on high quality and value for money. These bits have pilot-point designs, which means you usually won’t need to drill a pilot hole before using them.
They are also less likely to walk across the surface of the material while drilling. The sizes range from 0.062 inches up to 0.375 inches, which is less than some bit sets but should still be enough variety to tackle most tasks.
This set contains 5% cobalt, so the bits are M35 grade, and they can be used on hard metals such as stainless steel, angle iron, and I-beams.
Pros
- Pilot point design
- Doesn’t require pilot holes
- Value for money
- M35 grade
Cons
- Limited size range
- 5% cobalt
- Quality issues
Product Specs
| Number of pieces | 14 |
| Sizes (inches) | 0.063 to 0.375 |
| Tip | Pilot point |
| Grade | M35 |
| Price | $$ |
Our Ratings
Bosch 14-Piece Cobalt Metal Drill Bit Set
Best Professional Cobalt Drill Bits
Bosch is a name that is associated with German engineering quality and efficiency. This 14-piece drill bit set contains sizes ranging from 0.063 inches to 0.50 inches, so you will have a suitable bit for most drilling tasks.
Bosch has engineered these cobalt drill bits with professionals in mind, with split-point tips to prevent them from slipping while drilling. This means neater, more accurate holes.
These bits can also tackle less tough materials such as wood, plastic, and light gauge metals, making them great all-rounders.
Pros
- 14-piece set
- Engineered for professionals
- Split-point tips
- Bosch quality
- M42 grade
Cons
- Expensive
- Prone to snapping under heavy pressure
Product Specs
| Number of pieces | 14 |
| Sizes (inches) | 0.063 to 0.50 |
| Tip | Split-point |
| Grade | M42 |
| Price | $$ |
Our Ratings
Irwin Tools M35 Cobalt Drill Bit Set
Best Heavy-Duty Cobalt Drill Bits
This Irwin product is a 29-piece M35-grade cobalt drill bit set. The sizes range from 0.062 inches up to 0.50 inches. Each bit has a split point 135-degree tip to improve its accuracy and prevent it from slipping across the surface of the material while drilling.
These drill bits contain 5% cobalt and are designed for heavy-duty jobs such as drilling through stainless steel, cast iron, or titanium. They are contained in a professional-grade storage case lined with rubber. Removable cartridges make it easier to transport your bits wherever they are needed.
The only downside of this set is its price. It costs multiple times more than comparable sets from some of the leading tool brands. As a result, these bits will appeal to professionals more than amateurs, but they are an excellent option if you need a tough set of bits.
Pros
- M35 grade
- For heavy-duty use
- 29-piece set
- 135-degree tip
- Professional carry-case
Cons
- Very expensive
Product Specs
| Number of pieces | 29 |
| Sizes (inches) | 0.063 to 0.50 |
| Tip | Split-point |
| Grade | M35 |
| Price | $$$ |
Our Ratings
Comoware Cobalt Drill bit Set
Best Budget Cobalt Drill Bit Set
If getting value for money is your main priority, this set of Comoware drill bits is a great option. It is a 13-piece set, so it is less versatile than the larger sets on the market but it is also more affordable.
The sizes range from 0.062 inches to 0.25 inches, so they are suitable for small drilling jobs. The bits have 135-degree split point tips for improved traction, cutting ability, and less slipping across the surface of the material.
Your purchase includes a carry-case with a size index to make it easier to choose the correct bit. Overall, this is a set that contains good quality bits at an affordable price. It is an ideal set for beginners.
Pros
- Excellent price
- M35 grade
- 13-piece set
- Split point tips
Cons
- Limited size selection
- The bit holder is of poor quality
Product Specs
| Number of pieces | 13 |
| Sizes (inches) | 0.063 to 0.25 |
| Tip | Split-point |
| Grade | M35 |
| Price | $ |
Our Ratings
| 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 |
FAQs
Can Cobalt Drill Bits Be Sharpened?
It is possible to sharpen cobalt drill bits. The best tool for sharpening a drill bit is a bench grinder. Thanks to the extra durability of cobalt, these bits can be sharpened repeatedly without damaging them.
Are Cobalt Drill Bits Better Than High-Speed Steel (HSS) Bits?
Cobalt drill bits are better than HSS bits at coping with very high temperatures. This means they can be used for longer without dulling, so you won’t need to take as many breaks to allow them to cool down between tasks.
HSS bits are more prone to overheating, so they lose their edge more quickly. This can be reduced with lubricant or by cooling the bit between jobs to preserve it for longer.
The only negative is that cobalt drill bits are more brittle and prone to snapping so they might not be suitable for very difficult drilling jobs.
Are Cobalt Drill Bits Better Than Titanium?
Cobalt and titanium are suitable for different tasks. Titanium drill bits are better for general-purpose use, whereas cobalt drill bits will penetrate hardened surfaces better. Titanium bits perform similar tasks to HSS bits but can last up to 10 times longer. Cobalt drill bits have excellent heat resistance and can chew through steel, iron, and other smooth metals without losing their edge.
How Long Do Cobalt Drill Bits Last?
Cobalt drill bits are designed to be tough and durable, with many able to bore 1,000 to 2,000 holes in stainless steel before they are worn out. This is due to their high hardness rating, which helps them withstand the heat and pressure generated when drilling into metals.
Cobalt drill bits have a longer lifespan than high-speed steel (HSS) bits as they can retain their sharpness for much longer.
While they will naturally dull over time and eventually need to be replaced, cobalt bits can usually endure several months of frequent use before they are no longer useful.
Do Cobalt Drill Bits Break Easily?
Cobalt drill bits are usually very tough, even when drilling into hard materials. This is because they are made of a high-quality steel alloy that has greater resistance to extreme heat and high pressure.
However, they are also quite brittle and can become damaged or broken with improper use. This means applying too much force when drilling or failing to lubricate the bit so it can spin smoothly.
You should always choose an appropriate drill bit for the material you are drilling to prevent it from being overstressed and worn out prematurely.
What Is a Good Speed for Cobalt Drill Bits?
You should adjust the speed of your drill depending on the material you are working with. Generally, a speed between 1,000 to 2,500 RPM should be suitable for drilling any type of metal with a cobalt bit.
When drilling into softer materials such as wood or plastic, lower the speed to between 500 to 1,000 RPM. Higher speeds can cause the bit to overheat, which will lead to it becoming dull more quickly.
Always adjust your speed depending on the material, rather than how quickly you want to get the job done.
What Are the Different Grades of Cobalt Drill Bits?
Cobalt drill bits are made from a steel alloy, usually containing 5% or 8% cobalt that is added during the manufacturing process. These bits are given grades M35 or M42, which indicate the amount of cobalt they contain.
M35 indicates a cobalt content of 5%, whereas M42 has a higher cobalt content of 8%.
What Are the Best Cobalt Drill Bits?
The IRWIN 3018002 29-piece cobalt drill bit set is one of the best bit sets that are available. This 29-piece set contains bits of various sizes and types:
- Fractional
- Letter
- Metric
- Wire gauge
The 135-degree split point tip helps reduce slipping when drilling and ensures your holes will be precise. The cobalt steel construction improves durability and extends the lifespan of these bits compared to standard high-speed steel.
They also perform excellently. This set includes a convenient metal index storage case that protects them against damage when not in use or when you need to transport them from place to place.
