What Are The Best Drill Bits for Hardened Stainless Steel?

What Are The Best Drill Bits for Hardened Steel?

Do you need drill bits for your construction projects? Maybe you need to drill through hardened surfaces like hardened steel? What are the best drill bits for hardened steel? These are the questions that we’re going to answer today!

Drill bits are standard for making holes and precise cuts for construction purposes. Drills are used to bore holes through surfaces like hardened steel, whether you’re drilling a hole for screws or using them to install wall anchors.

Today, we’re going to learn what makes a good drill bit for hardened steel, factors that affect choosing the right drill bit, the best drill bits for hardened steel, and some related questions about drill bits for hardened steel.

What Makes a Good Drill Bit for Hardened Steel?

Creating precise and accurate holes in wood, steel, and concrete requires drill bits. According to Sign Builder Illustrated, due to the combination of speed, pressure, and torque that’s needed to bear down and penetrate these materials, drill bits are necessary for the job.

Drills have been standard tools and have been with us since the 1800s. The electric drill may be one of the most efficient tools humankind has made since it makes hand tools obsolete.

There are just so many advantages when using a drill compared to using your hand to pierce through objects. Unlike machines, there’s so much room for error if drilling holes were made manually with a hand tool.

So, let’s start with the question, what makes a good drill bit for hardened steel? Drills are often used on different surfaces. In our case, we’re looking for a drill bit that’s well suited for hardened steel.

What Makes a Good Drill Bit for Hardened Steel

The list below shows the features and characteristics your drill bit should have for drilling through hardened steel:

  • Comes in a Set

The drill bits you should buy should preferably come in a set. Why? Simply because if you’re looking to buy a drill bit, you’re most likely going to use different sizes in the future as well.

So if it came as a set, it would be incredibly helpful since, first, you’ll save money (buying them as a group instead of purchasing them separately), second, you can use them in the future, and depending on the brand, it might even come in a plastic box where you can store the bits.

  • Material It’s Made of – Durability

The standard material used for drill bits made for hardened steel is cobalt. It is compact but also robust, and it’s also great when dealing with high-temperature drilling.

So, if you’re planning to buy drill bits used explicitly for hardened steel and metal drilling, make sure you choose a drill bit that’s made out of cobalt. Other drill bits (like Titanium drill bits) aren’t significant when working with hardened steel. Instead, they’re used for wood and soft metals.

  • Length and Hole Diameter

Similar to the first feature drill bits should have, you must have a wide variety of choices when it comes to having different drill bit lengths and diameters. Other holes require different drill bits, especially when you need precise cuts.

For example, drilling a pilot hole for wall anchors requires a separate drill bit compared to making holes on wood that needs a larger hole. That is the importance of having different drill bits with different lengths and diameters.

  • Strong Heat-Resistant Drill Bit

This is an essential factor that can often be overlooked even by experienced people in the construction and home repair industry. The drill bits should be heat-resistant, especially in our case, when choosing drill bits for hardened steel.

Why does this happen? Metal has strong conduction properties, and this means when it creates friction with another metal, it tends to overheat.

When drilling into hardened steel, the drill bit is exposed to that intense heat. That’s why heat-resistant drill bits are a great feature to have to make sure that your drill bit provides excellent quality over time.

Factors That Affect Choosing The Right Drill Bit for Hardened Steel

Now we know what makes a good drill bit, we should consider the other factors that affect you, the buyer, choosing the right drill bit for hardened steel. Since hardened steel is a different surface compared to what we normally use our drills for, there may be things you need to know.

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Here’s an example video of Drilling Hardened Steel Fast and Slow where you’ll know what to do when drilling through hardened steel.

The Surface’s Hardness – How Hard is Hardened Steel?

The surface’s hardness is very important when it comes to choosing the right drill bit. There are three types of widely known drill bits in the drilling industry, the HSS (High-Speed Steel), Cobalt Drill bits, and Carbide drill bits.

Here are the surfaces appropriate to each type of drill bit out there:

  1. HSS (High-Speed Steel) is preferred for surfaces such as wood, soft metal, and other related surfaces with the same hardness.
  2. Cobalt Drill Bits– This is used to drill hard surfaces like hardened steel and can cope with the high heat it has to deal with while drilling.
  3. Carbide Drill Bits – Similar to Cobalt drill bits, these can also be used for steel and sometimes even applications on fiberglass and other nonmetal surfaces.

The list above should be a basic guide on knowing which drill bit suits the job best. As you can see from the list, cobalt drill bits are well-suited when drilling through hardened steel, so you better buy drills made out of cobalt drill bits for great results.

The Drill Bit’s Coating – Which is Best Suited for Hardened Steel?

Similar to the many different drill bits available in the market today, there are also bits equipped with different kinds of coating as well. Although it won’t make a significant difference compared to the type of drill bits you use, it’ll help a lot knowing the different coatings.

  1. TiN Coating and TiAIN Coating – Titanium nitride coating and titanium aluminum nitride coating offer extra lubricity at their drill coat and are great for high-speed drilling and last a long time.
  2. Black Oxide Coating – This is one of the most common coatings that help to retain the lubricants for a smoother drilling experience. However, it’s not recommended to use this with non-ferrous metal like aluminum.

Bright Finish – From the name itself, the bright finish is simply the bare metal of the drill bit. No coatings at all. This option is great for non-ferrous metals like aluminum steel.

The Compatibility of the Drill Bits

This is a factor that significantly affects choosing the right drill bit for hardened steel. You need to ensure that the drill bits you buy are compatible with the actual drill you’re using.

Compatibility of the Drill Bits

One way of finding out the drill bit’s compatibility is by reading your drill’s manual, reading reviews online, or you can also try asking the drill manufacturer’s customer service hotline if you have any more queries about their products.

What Are The Best Drill Bits for Hardened Steel? Top Picks and Recommendations

So, now that you know what makes a good drill bit, factors that affect choosing the right drill bit for hardened steel, now we’re going to recommend you some choices for you and make these products as a base guideline when it comes to picking the right drill bits.

These are some of the products we found on the internet that might be helpful for you, and we’re going to list the pros, cons, and our conclusion on what the product can offer you.

The list we’re sharing below is not arranged in any order. However, these drill bits are our top picks, so you really need to take your time reading each pro, con, and conclusion we offer you to make sure you’re getting the most out of your money.

Here’s the list of recommendations for the best drill bits for hardened steel:

1. IRWIN Drill Bit Set

The IRWIN Drill Bit Set is a great set when it comes to multi-purpose drilling. Since the drill bit’s made out of cobalt steel, it’s great for multiple drilling applications.

For example, do you want to drill on hardened steel? It’s capable of that.

That’s the advantage of having cobalt steel drill bits; they have multiple uses compared to other drill bits that are specifically tailored to drilling some surfaces only.

The drill set also comes as a 15-piece set which means you have a lot of bits to choose from.


Here are the pros of the IRWIN Drill Bit Set. Use this list as a guide to knowing the advantages of purchasing this set of drill bits:

  • Stackable and Portable– Bring it everywhere and anywhere you need it.
  • Redesigned Drill Bit Tip– For longer drill bit life.
  • Visible Clear Lid– This makes it easier to view the contents of the bit set.
  • Many Sets to Choose From– Can come in a 15-pc, 21-pc, and 29-pc set.
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Here are the cons you might find helpful to know before buying the IRWIN Drill Bit Set. Maybe you need to think twice before purchasing this drill bit set:

  • Some Products Are Defective – Some past reviews and users online claim that their drill bits are deemed ineffective and don’t even scratch the surface of the metal.

What do you think of the product so far? Let’s do a little recap, you’re getting a 15-piece drill bit set that’s made out of cobalt steel, and it even comes with a tiny toolbox for drill bits to make sure your bits are organized and stored in a safe place.

Since it also has a budget-friendly price, we recommend you to purchase this IRWIN Drill Bit Set made out of Cobalt Steel because it’s a bang for the buck. It’s the perfect balance between price and quality.

2. IRWIN Drill Bit Set, M35 Cobalt Steel

This is the second time that IRWIN has shown up on our top picks of drill bits list. This proves how reliable IRWIN Drill Bit Sets are and why they deserve two spots on the list of our top picks.

However, we’re going to discuss what makes this drill bit set, in particular, an excellent choice compared to the other drill bit sets in the list. It has a titanium nitride and a black oxide finish, made out of cobalt steel, and has a 135 Degree cutting angle swing.

For starters, it can come in 15-piece, 21-piece, and 29-piece drill bit sets. Right off the bat, the drill bits offer different sets with different drill bit lengths.

Without talking too much about why it’s a great drill bit set, let’s dive into the pros of how it became a great drill bit set for customers like you and me trying to buy drill bits for hardened steel:


Here are the pros of the IRWIN Drill Bit Set – Jobber Drill Set that’s proving to be a good choice for buying your drill bit sets:

  • Built for Abrasive Surfaces – Like most IRWIN Drill bits out there, the drill bit set is made of M-42 5% cobalt steel suitable for drilling on abrasive surfaces.
  • Metal Index Case – Compared to the previous IRWIN Drill Bit Set, it has a metal index case that is a lot smaller and more compact than the previous drill bit case.
  • Short Cutting Lips – Having shorter cutting lips will reduce the torque needed to drill through high-tensile materials, faster and more precise cuts.
  • Heavy Duty Spiral Flute Design– The heavy-duty spiral flute design will make sure it creates accurate cuts on holes without requiring too much power.


Although most of the IRWIN Drill Bit sets come with the same complaint, it’s also great if we are constantly reminded with a heads up of the cons before buying IRWIN Drill Bit Sets:

  • Defective Materials Shipped – Even though it’s not a common occurrence, you have to take note that sometimes they mistakenly ship you a defective product. In that case, you may need to contact their refunding services.

Like the previous IRWIN Drill Bit Set featured on the list, we highly recommend you buy this IRWIN Drill Bit Set, Cobalt Steel, Jobber Drill Bits because they’re highly usable in drilling situations where you need to drill through surfaces like hardened steel.

It’s made of cobalt steel, comes with a metal index case, has a heavy-duty spiral flute design, and short cutting lips to produce torque while drilling. To us, it’s a must-buy.

3. Drill America

The next drill bit set on our list is not from IRWIN but Drill America. American tools are widely known for their quality to precision cuts and holes their drill bits make.

However, compared to the previous IRWIN drill bit sets, what makes these drill bits different?

So let’s talk about the most important things we need to know about them. They’re made of cobalt steel, have a gold finish, and come as a 29-piece drill bit set.

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They are also classified as jobber drill bits with a round drill bit case for easier portability.

Without further ado, let’s talk about the pros, cons, and our conclusions based on the product’s specifications and features:


Here are the pros of Drill America’s DWD29J 29-Piece Drill Bit Sets that you need to know! These pros may convince you to buy their product even more:

  • Made out of Cobalt Steel – Using Cobalt steel for drill bits is ideal because they’re practical and durable when drilling on abrasive and challenging surfaces like hardened steel.
  • Gold Oxide Finish – This type of finish will provide you with extraordinary lubrication and better wear resistance than other drill bits with a bright finish.
  • Round Plastic Case – Although it’s somewhat of a unique design when it comes to storing the drill bits and a little bit messy, it does a good job when it comes to keeping the drill bits. However, it’s not as organized as it seems.
  • Self-Centering 135-Degree Split Point – Having a self-centering 135-Degree split point bit will only mean that it will continue to drill in a straight line and not require that much readjustment.


After this statement, the following list is what you need to note before you even consider buying the Drill America Drill Bit Sets. This is to let you know the disadvantages of purchasing this drill bit set:

  • The Drill Bit Case– Although it keeps all the drill bits together, it’s doing a terrible job when it comes to differentiating different drill bits and sizes since they’re stored with each other compared to other cases where each bit is labeled.
  • Price – Compared to other cobalt steel drill bits, they have a heftier price tag compared to other competing brands.

Other than the poor design of the drill bit’s case, it’s a good drill bit. However, the price tag doesn’t seem friendly to most people out there. If you have the luxury to spend this much, then we can recommend you to buy it.

Realistically speaking, there are better options out there with the price they’re offering. Regardless, they provide significant drill bits, and their quality is as good as the other competing brands.

Choosing the right drill bit will make it easier for the worker to get the job done, especially if the drill bit is tailored to do a specific task/job that a worker needs to do.

For example, you need cobalt steel drill bits to drill through hardened steel.

However, when it comes to choosing wood drill bits, they are fine with using HSS (High-Speed Steel) since wooden surfaces aren’t as hard as steel.

Related Questions

What can drill through-hardened steel?

Generally speaking, the best material that can be put in drill bits that are well suited for drilling through various metals is HSS (High-Speed Steel), Cobalt Steel, and Titanium Steel. When it comes to hardened steel, Cobalt steel is the most preferred choice.

Are cobalt bits enough for drilling through hardened steel?

Of course! They’re the better-suited type of material when it comes to piercing through reinforced materials like hardened steel. This is widely used in the construction industry, especially when it comes to building high-rise buildings. You need to drill holes on hard metal.

Do I need to use an expensive drill to drill through hardened steel?

As long as it provides the necessary torque and power to drill through the hole, then you won’t require an expensive drill to complete the job.

Can I use these drill bits for stainless steel?

Of course, the list above is limited to using them for hardened steel and stainless steel. Since they’re great for abrasive surfaces, dealing with soft metals, wood, and any other similar application should be doable by the drill bits above.


I’m Brian, a car fanatic, and the founder of DrillandDriver.com, I’ve been into cars my whole life. Actually, not just into them but obsessed with them. I have been working as a mechanic for over 15 years and have been deeper into the motor and electric vehicles for some years.

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