The Best Drill Bits for Metal, Tested on Steel, Iron, and More

Home improvement centers often dedicate an entire aisle to drill bits, which come in a range of types and sizes for drilling into a variety of materials. While many bits can handle wood and masonry, not all are built to power through metal without overheating or snapping. Fortunately, most tool manufacturers label drill bits for their intended use, making it easier to choose the right set for your project. Still, some options perform better than others for various types of metal. 

To help you choose the right set, we researched top-rated picks and tested seven of the most popular. After drilling through tough steel and other metals, we chose the Bosch BL21A 21-Piece Black Oxide Metal Drill Bit Set as the best overall set for its reliable performance, lasting sharpness, and ability to stay cool during use. If you’re working on a project that requires drilling through metal, read on to learn more about the best drill bits for metal and which factors matter most when shopping for them. 

1. BEST OVERALL: Bosch BL21A 21-Piece Black Oxide Metal Drill Bit Set
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2. BEST BANG FOR THE BUCK: DeWalt DWA1184 Black and Gold Drill Bit Set
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3. UPGRADE PICK: Bosch CO14B 14-Piece M42 Cobalt Steel Drill Bit Set
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4. BEST COBALT: Irwin 63137 15-Piece M42 Cobalt Steel Drill Bits
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5. BEST HEAVY-DUTY: Drill Hulk ¼-Inch Cobalt Steel Twist Drill Bit Set
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6. BEST FOR STEP DRILLING: Comoware 5-Piece Titanium-Coated Step Drill Bit Set
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7. ALSO CONSIDER: Irwin 3018002 29-Piece M35 Cobalt Steel Drill Bits
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Drill Bits for Metal Comparison

Our Top Picks

The following drill bits for drilling metal all performed well in our tests. Depending on your needs, one should be just what you need for your next repair or build. 

Best Overall

Bosch BL21A 21-Piece Black Oxide Metal Drill Bit Set

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What We Like

• Surprisingly sharp for general-purpose bits 
• Drilled holes in heavy-duty steel faster than others
• Remained cool during use

What We Don’t Like

• Rounded shanks can spin when exiting the material

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Specs 

• Material: High-speed steel (HSS)
• Coating: Black oxide
• Shank type: Smaller bits are round; larger bits are no spin

Those looking for an all-around capable set of drill bits may want to check out the Bosch black oxide metal drill bit set. Made from high-speed steel and coated in black oxide, these bits resist heat and friction, allowing for continuous drilling without overheating. The 21-piece set includes sizes from 1/16 inch to ½ inch, all stored in a compact plastic case. 

This Bosch high-speed drill bit​ set features tapered tips that can quickly penetrate metal, keep the bits balanced, and produce clean, even holes. While we’re not typically huge fans of general-purpose bits (especially when it comes to working with metal), this set was excellent. The bits didn’t walk when starting a hole, and they removed long metal shavings—clear signs they were staying sharp. They also worked faster than anything else we tested and stayed cool to the touch during testing (while using cutting oil).

The one drawback of this set is that the smaller bits have rounded shanks, which can spin slightly when the bit is about to drill all the way through the material. However, the larger bits have no-spin shanks that do a great job of staying in place. Overall, this Bosch set exceeded expectations, offers a great value, and provides versatility for a range of tasks.

What our tester says: “These Bosch bits really surprised us. We were so shocked that they were so good that we kept drilling with them to see if it was a fluke—and it wasn’t.”—Tom Scalisi, Product Reviews tester and writer 

Get the Bosch BL21A drill bits for metal at Amazon or Tractor Supply Co.

Best Bang for the Buck

DeWalt DWA1184 Black and Gold Drill Bit Set

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What We Like

• Split-point tips didn’t walk at all 
• Very good metal drill bits at a great price
• Sharper and faster than some more expensive kits

What We Don’t Like

• Small bits have rounded shanks that spin a bit

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Specs 

• Material: HSS
• Coating: Black and gold coating
• Shank type: Smaller bits are round; larger bits are no spin

Folks who need to drill a few holes in metal but don’t want to spend more than they have to will want to consider the DeWalt DWA1184 black and gold drill bit set. This affordable, all-purpose set includes 14 high-speed steel bits ranging from 1/16 inch to ½ inch. Each bit has a 135-degree split-point tip to help prevent walking, plus Dewalt’s signature black and gold coating to resist rust. They come in a clear storage case for easy organization and quick access.

To be 100 percent upfront, we’ve never liked DeWalt drill bits. Previous options we’ve tried have been relatively low quality and felt like throwaways. But this particular set was incredible when it came to drilling metal. They didn’t walk at all and cut long, continuous, spiraled shavings. With a little lubricant, they stayed cool, too. The rounded shanks on the smaller bits did spin a little, but the no-spin shanks on the larger bits were great. And, surprisingly, this multiuse budget kit drilled through wood faster than some of the much more expensive bits we tested, making it a solid option for a range of drilling needs. 

Get the DeWalt drill bits for metal at Amazon or The Home Depot.

Upgrade Pick

Bosch CO14B 14-Piece M42 Cobalt Steel Drill Bit Set

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What We Like

• Split-point bits are easy to sharpen 
• 3 flat sides on the shank eliminate slipping 
• M42 cobalt is superior to M35 alloy

What We Don’t Like

• Hard to read size labels on carry case

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Specs 

• Material: M42 cobalt steel
• Coating: No separate coating
• Shank type: Smaller bits are round; larger bits are no spin

With its M42 cobalt drill bits, this set from Bosch is ready to take on the hardest metals. The 8 percent cobalt alloy is more durable and heat resistant than what’s used for M35 cobalt drill bits, giving the bits a longer lifespan. The 14-piece kit includes common bit sizes between 1/16 inch and ½ inch and comes in a plastic case for easy storage. 

These bits have several design features that make them especially effective for metal. The split-point tips penetrate metal easily for accurate starts, while the 3-flat shanks prevent slipping in the chuck. They also have a thicker threading than most spiral drill bits, which helps remove material more efficiently and reduces overall drilling time.

We tested these bits using both a cordless drill and a drill press to evaluate performance in different setups. The cordless drill mostly worked well, though maintaining a slow, steady speed in steel was slightly more difficult with its variable speed trigger. The drill press allowed for greater control and precision, especially when drilling harder materials like cast iron. Overall, we liked the secure chucking, smooth drilling, and easy sharpening these bits offered. 

Get the Bosch CO14B cobalt drill bits at Amazon or The Home Depot.

Best Cobalt

Irwin 63137 15-Piece M42 Cobalt Steel Drill Bits

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What We Like

• Durable M42 cobalt drill bits for hardened steel
• Case keeps bits safe and organized
• Stayed cool and sharp, even after drilling multiple holes

What We Don’t Like

• Round shank spun in chuck at times

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Specs 

• Material: M42 cobalt alloy steel
• Coating: No separate coating
• Shank type: Round

If you’re looking for high-quality drill bits for metal that are made to last, the Irwin 63137 set is worth considering. Made from cobalt high-speed steel, they’re designed specifically for hardened steel and other tough materials. They have 135-degree split-point tips to help prevent walking when starting a hole and offer excellent resistance to wear and heat. Bit sizes range from 1/16 to ½ inch wide, and the bits larger than ⅜ inch wide have reduced shanks.

In testing, these Irwin bits performed well. They didn’t walk during hole starts and bored through metal at a steady, reasonable pace. They also stayed cool while drilling and retained their sharp edges, even after several holes. Our biggest complaint is the rounded shanks on the smaller bits, which spun slightly in the chuck. The case was also a bit flimsy due to its plastic tab closure, but it still does a good job keeping these bits safe and organized. 

Get the Irwin 63137 drill bits for metal at Amazon.

Best Heavy-Duty

Drill Hulk ¼-Inch Cobalt Steel Twist Drill Bit Set

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What We Like

• Heavy-duty bit with a 135-degree tip 
• No-spin shanks prevent sticking in the material 
• Set of 12 to replace the most frequently used bits

What We Don’t Like

• Still walked slightly upon starting

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Specs 

• Material: M35 cobalt alloy steel 
• Coating: No separate coating
• Shank type: No spin

DIYers and pros who go through a lot of ¼-inch drill bits for heavy-duty metalworking projects may benefit from the Drill Hulk’s ¼-inch cobalt steel set. This 12-pack features jobber-style bits (long drill bits relative to their diameter) for better reach and versatility. They’re made from durable M35 cobalt high-speed steel, feature 135-degree split points for drilling through metal without walking, and have a no-spin shank to prevent slipping in the chuck.

These bits are built for hard use. In testing, they retained a sharp edge while drilling through thick ¼-inch steel, stayed cold during use, and bored cleaning without stalling. The no-spin shank worked as intended, keeping the bits secure in the drill.

While we don’t have an immediate need for a dozen ¼-inch drill bits, we like that full-time shops can stock up on their most-used size without buying a full kit of extras. However, we did notice that these bits can walk slightly, despite the 135-degree split point, though it was minimal and easy to control.

Get the Drill Hulk drill bits for metal at Amazon. 

Best for Step Drilling

Comoware 5-Piece Titanium-Coated Step Drill Bit Set

See It

What We Like

• 50 different sizes between ⅛ inch and 1⅜ inch 
• HSS steel and titanium coating resist rust and wear
• Great for quickly enlarging existing holes to the desired size

What We Don’t Like

• Not quite sharp enough to start their own holes in metal

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Specs 

• Material: HSS
• Coating: Titanium
• Shank type: No spin

When it comes to enlarging hotels in metal, a step bit like the ones in this five-piece kit from Comoware is the right tool for the job. Each bit features multiple steps, with the full set covering 50 sizes ranging from ⅛-inch to 1 ⅜-inch wide. The bits are made from high-speed steel for strength and coated in titanium to reduce friction and increase durability. The kit also comes with a spring-loaded center punch for marking holes and a carrying case with foam recesses to keep everything organized.

We really liked these bits during testing, though we did find that they were better for enlarging holes than actually drilling them (at least when it comes to metal). While the tips weren’t sharp enough to start holes cleanly, we could quickly work up to the desired size with the Comoware after we used another bit to make a pilot hole. We also appreciated the wide size range and the useful center punch for accurate starts.

Get the Comoware drill bits for metal at Amazon. 

Also Consider

Irwin 3018002 29-Piece M35 Cobalt Steel Drill Bits

See It

What We Like

• Sizes between 1/16 and ½ inch in 1/64-inch increments
• Made from M35 cobalt for durability and edge retention
• Sturdy case has spring-loaded latch and size guide 

What We Don’t Like

• All bits have rounded shanks

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Specs 

• Material: M35 cobalt alloy steel 
• Coating: No separate coating
• Shank type: Smaller bits are round; larger bits are reduced 

Avid metalworkers looking for professional-grade bits may want to consider the Irwin 29-Piece cobalt alloy steel drill bits set. This comprehensive kit includes 29 drill bits ranging from 1/16 inch to ½ inch in 1/64-inch increments, making it easy to find a bit for almost any size hole. Though all shanks are round, bits larger than ⅜-inch wide are reduced in size to fit standard chucks.

These bits are made from durable M35 cobalt alloy high-speed steel, helping them retain a sharp edge while drilling. Each one fits neatly into the sturdy, hinged case, which features a spring-loaded latch to keep it securely closed. The case also includes a built-in tap size guide to help match bits to bolts or fasteners and rubber molding on the bottom to keep it from sliding.

In testing, these Irwin bits didn’t cut quite as fast as some others, but they held a sharp edge and didn’t walk at all during starts. However, every bit, despite its size, features a rounded shank, which led to a little slippage. 

What our tester says: “These weren’t the fastest bits we tested, but they stayed sharp and never walked. Their size range and the included tap chart make them a solid pick for serious metalwork.”—Tom Scalisi, Product Reviews tester and writer 

Get the Irwin 3018002 drill bits for metal at Amazon.

Jump to Our Top Picks

How We Tested the Best Drill Bits for Metal

There’s only one good way to find the best drill bits for metal: drill into some metal. After grabbing some scraps of metal off our welding cart, we chucked some bits into our drill and started drilling. 

We started with relatively light-duty 11-gauge steel angle iron, testing several bits from each pack. We looked at how well they held their edge, how hot they got, and how long they took to bore a hole. We then changed the drill bits and moved on to heavier material. 

Next, we tested bits in 7-gauge flat stock to see how they performed under tougher conditions. We did our best to maintain similar speeds and pressure throughout each portion of every test. Afterward, we used a drill bit sharpener to sharpen larger bits to evaluate ease of maintenance. The bits that performed best were given awards based on their strengths.

What to Consider When Choosing Drill Bits for Metal

Most types of drill bits fit both standard corded and cordless drills. While these small pieces of metal all look pretty similar, each is designed to make holes in specific materials, such as wood, plastic, concrete, or metal. 

Bits that drill through metal are further classified by the types of metal they puncture. For example, a bit for drilling through ferrous metal, such as cast iron, may not be the right choice for boring through nonferrous metals, such as copper and tin.

Drill Bit Material 

Most drill bits are made from HHS, cobalt, or carbide. A bit’s material can influence how effective it is at drilling through different kinds of metals.

• HHS: This is an all-purpose drill bit that can be used to drill through both ferrous and nonferrous metals as well as carbon steel.
• Carbide: Metal-drilling bits made from carbide are suitable for drilling nonferrous metals but not ferrous metals. Carbide bits are also often used to drill through tile.
• Cobalt: Cobalt drill bits work well for drilling ferrous metals but may not be as good at drilling nonferrous metals.

Coating

Drill bit coatings affect how a drill bit operates. Unless they’re made of cobalt alloy steel and therefore uncoated, many drill bits come with a layer of titanium or black oxide covering them. This coating is designed to reduce friction, which keeps the drill bit from heating up and eventually breaking. Because the coating reduces friction, it can also help increase drilling speed.

Shank Design

The shank is the nondrilling end of the bit that fits into the drill’s mandrel or chuck. For hex shank bits, the shank size of the bit chosen (typically ¼ inch, ⅜ inch, or ½ inch wide) should match the chuck size of the drill. 

Some shank designs are more conducive to drilling through metal than others. Most shanks for this type of drill bit are either no spin or hex.

• Round shank: These bits have completely rounded shanks. They don’t help prevent slipping.
• No-spin shank: This type of drill bit has a fluted shank that is designed to keep the bit from slipping when drilling.
• Hex shank: Similar to the shape of some screwdriver bits, a hex shank has six sides that help the bit remain steady while drilling into hard metals.

Tips for Buying and Using Drill Bits for Metal

Researching shank design, bit material, and bit coatings might be confusing at first, but most of the best drill bits for metal are labeled by both the size of the hole they’ll drill and the type of materials they’re for. 

To find the sharpest drill bits for metal, look for the words “metal drilling bit” on the package, followed by a list of metals the bit is designed to puncture. Here are a few additional tips for using these power drill attachments to drill smoother holes and keep bits in tip-top shape.

• Use a center punch to create a depression in the metal before drilling. This will reduce the likelihood of the bit slipping off the material to be drilled.
• Use a lubricant while drilling. A drop of three-in-one oil or cutting fluid will lubricate the drill bit, making drilling easier and reducing wear and tear on the bit. 
• The friction generated by the bit drilling through the metal can cause the bit to heat up and break. This is especially true with larger bits. By drilling slower and taking breaks every few minutes to let the bit cool down, these long metal drill bits should last longer.

FAQs 

Whether you’re just getting into metalwork or want to expand your drill bit set, metal drilling bits can be a good investment. However, if you still have a couple of questions, the answers below can help. 

Q. Is a cobalt or titanium drill bit better? 

It depends on what kind of metal you’re drilling through. Titanium drill bits for metal are suitable for drilling through soft metals such as aluminum, while cobalt bits are better suited for drilling through hard metals like cast iron.

Q. How can you drill through thick metal?

The best way to drill through thick metals is to use a drill press rather than a handheld drill—a press best achieves a clean, smooth hole. Be sure to drill slowly and use cutting fluid to lubricate the bit, too. Let the bit cool down every few minutes to keep it from overheating and breaking.

Q. How can I sharpen my drill bits for metal?

Many DIYers don’t bother sharpening their bits when the cutting edges become dull and they have trouble drilling a hole, but it’s tool maintenance worth doing. You’ll get a longer life out of your drill bits if you sharpen their cutting edges with a bench grinder. 

Q. Do I need to clean drill bits after each use?

It’s not a bad idea to clean drill bits after using them. After drilling, wipe away any residue on the bit with a soft cloth and then rub a bit of cutting fluid on it before storage.

Q. How do I remove a broken drill bit from metal?

Add a drop or two of lubricating oil to the bit and then grab the broken end of its shank with a pair of pliers. Twist counterclockwise to remove.

Meet the Tester

Tom Scalisi has been in the trades for over two decades. He loves to share his knowledge of construction, home improvement, tools, techniques, and products with the readers of Bob Vila, This Old House, Family Handyman, and even his pest control website, Riddabugs.com.

Additional research provided by Glenda Taylor and Mark Wolfe.

 

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