Best Drill Bits for Metal

Last Update: August 12, 2021

Best Drill Bits for Metal

Over the years, we’ve used and/or tested dozens upon dozens of drill bits for nearly all applications. In this go-around, we wanted to identify the best drill bits for metal applications. That includes hardened steel, stainless steel, aluminum, and more. We even wanted to see which drill bits worked well for drilling out hardened bolts as you might find in an engine block. People also ask us about bits that handle drilling through rebar. These are the bits we turn to and should steer you in the right direction.

Home improvement centers often dedicate an entire aisle to drill bits, which come in a plethora of types and sizes for drilling holes in a variety of materials. Many drill bits can pierce through more than one type of material, but not all drill bits can drill through metal without heating up and snapping in half. Labels on drill bits indicate the type of material for which they’re suited, so it’s easy enough to find ones that are designed to drill metal. Depending on the type of metal you’re drilling, some bits suit the task better than others.

If you are working on a project that requires you to drill through metal, read on to learn about the factors you should consider before you go shopping for the best drill bits for metal. The following drill bit sets rise above the competition and will help you make holes in myriad metals.

How Drill Bits for Metal are Different from Other Drill Bits

Drill bits that are cut out for handling metal surfaces contain special coatings or are made of certain materials that can handle the friction, heat, and resistance the bit faces when tasked with drilling into metal. Bits made of soft carbon tool steel are not built for this kind of work and can break under pressure or result in damaged tools and injury.

When it comes to bits that can handle this kind of intense drilling, you’ll want to be searching through bits made from High-Speed Steel (HSS) and Cobalt High-Speed Steel. The latter is more durable for harder metals, such as cast iron, whereas the former does better with softer materials. Coatings made of titanium, black oxide, diamond, and zirconium can also boost the drill bits’ durability and ease up on friction.

There are also different bit shapes that make it possible to work with metallic surfaces. A more common version, the twist bit, for instance, is a great option, as well as hole saws, both of which can be ideal when handling different types and hardnesses of metal.

Tips for Buying and Using Drill Bits for Metal

Researching shank design, bit material, and bit coatings can be confusing, but fortunately, drill-bit manufacturers make shopping relatively easy for the customer. Drill bits are labeled not only by the size of hole they’ll drill but also by the type of materials they’ll drill. 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 that will help you drill smoother holes and keep your bits in tiptop 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 as you drill. 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, your bit will last longer.

What Do We Mean By Hardened Steel?

When we talk about drilling in hardened steel, we mean medium or high carbon steels typically made using a heat-treatment and tempering process. Hardened steels are durable and can be wear-resistant, corrosion-resistant, and abrasion-resistant. Much of the steel materials that we see used in mechanical engineering, energy generation, and transportation are basically hardened steel. The best drill bits for metal could be designed for these hardened steel applications or they might be optimized for speed in softer carbon steels.

Stainless Steel

Stainless steels are steel alloys consisting of at least 10.5% chromium and there are different grades. Because of rust and stain resistance, good luster, and low maintenance, it has many commercial uses including cookware, cutlery, home appliances, construction fasteners, and surgical instruments.

However, whatever differences there are between the outer look or chemical composition, both hardened steel and stainless steel are quite difficult to drill into. Using a drill press is often the best way to get quality results.

Our best drill bits for hardened steel include the following:

1. Hymnorq Jobber Twist Drill Bits 15pc Set

The tapered noses and twisted side grooves of the bits in this Hymnorq set quickly penetrate many hard metals including iron to drill a steady, self-centering hole. The bits also work well for drilling softer metals, such as aluminum and copper.

The downside is they are not suitable for drilling the hardest types of metal, including titanium and high-carbon steel. Made from cobalt steel combined with molybdenum for added durability, the Hymnorq bits are friction and heat resistant. This set features 13 bits that range in size from 1/16 inch to 1/4 inch to cover your metal drilling needs.

2. Irwin 29-piece Cobalt M-42 Metal Index Drill Bit Set

Irwin 29-piece Cobalt M-42 Metal Index Drill Bit Set

If you plan on drilling hardened metal or steels, we love the Irwin 29-piece M-42 Cobalt bit kit as our the best metal drill bit set. Honestly, it’s not the fastest drilling bit that gets it our nod. It has to do with the use of M42 high-speed steel and its excellent case.

Many less expensive cobalt drill bits use M35 steel which has a 5% cobalt blend. M42 steel uses an 8% cobalt blend. This gives it a greater hardness. It also lets you drill at higher speeds than M35. Irwin actually sells an M35 cobalt set if you don’t plan to drill hardened steel.

Which brings us to the case. If you do a lot of drilling—the case your bits come in matters. Accessing bits can be frustrating (we’re talking to you Milwaukee!) or hugely successful—like with this Irwin three-tier swing case. We love the easy-access bits, and you can easily tell the sizes from the front of each bit. Overall, this kit gives you the best drill bits for metal applications of all kinds.

3. BOSCH Drill Bit

BOSCH Drill Bit

If your primary concern is accuracy, then you’ll love working with the BOSCH Drill Bit. It’s suited for heavy-duty tasks, delivering much-needed stability to get the desired output. Therefore, it has quickly climbed the charts to cement a place among the top units, and we assure you won’t be disappointed.

The first impression of the unit is that it looks like a pencil. It’s easy to see how you can be mistaken, given its refined shape and the special attention to details. The drill bit comes with a no skate tip, ensuring accuracy in your tasks.

We noticed the designers used high-carbon steel for the construction, making it extremely durable. You get to use it for a long time, in different conditions, which speaks volumes about consistency. Therefore, it performs well on heavy-duty projects and reduces work time while increasing productivity.

Another terrific addition is the long flute, allowing you to remove debris for a seamless experience. It permits you to make the desired cut, thanks to the impact-rated shank, meaning you can work from various angles. Plus, it delivers higher torque and is well complemented by the titanium coating to keep friction to a minimum.

4. DEWALT Titanium Drill Bit Set

DEWALT Titanium Drill Bit Set

Getting through hardened steel can be difficult if you’re not using the right drill bit. If you’re using the wrong drill bit, the point may bounce back or dance across the surface instead of making a dent in the tough substance. DEWALT created the Titanium Pilot Point drill bit set to power through the often difficult process of drilling into hardened steel; the bits are highly durable and resist chipping, stalling, or dulling, even after many uses.

This set of 21 titanium drill bits is made to last. The bits are ideal for a number of jobs in a wide range of industries, from drilling out broken bolts, adjusting manifolds, or removing exhaust systems, to fixing or installing car engine parts. These drill bits are designed to prevent chipping in the hardened steel and to dissipate the heat that can build when working with this durable material.

5. Neiko 10193A Titanium Step Drill Bit Set

Neiko 10193A Titanium Step Drill Bit Set

This set of step drill bits are made from high-speed steel and coated in titanium to increase their longevity and decrease their dulling from heat and friction. What these step bits do is give you 28 size options but with just 3 drill bits.

The sizes range from 0.188 inches up to 0.75 inches. So, whatever the size of the hole, this set has you covered. The tips are 135-degree split points, which are the ideal style for drilling through metal. It decreases the chances of the bit wandering on the surface of the metal. This set also benefits from a tri-flattened shank to stop the drill bits moving in the chuck.

Taking Care of Your Drill Bits

Once you have bought your drill bits there are some measures which you can take to protect them and extend their life. By employing the following guidelines you should prevent unwanted damage to your drill bits.

  • Always use a metal cutting paste or lubricant when drilling metal
  • Drill at the correct drilling speed or if in doubt drill at a slow speed
  • Only use required pressure
  • Drill in stages and allow short breaks between drilling sessions

All of the above are designed to prevent excessive heat build up which is one of the major contributors to drill bit damage.

FAQs

Whether you’re just getting into metalwork or you want to expand your drill bit set, adding metal-drilling bits to your arsenal of tools is a good investment. If drilling through metal is a new endeavor for you, you likely have some questions.

Is a cobalt or titanium drill bit better?

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

How can you drill through thick metal?

The best way to drill through thick metals is to use a drill press rather than a hand drill—a press will get you 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.

What is a left-handed drill bit?

Most bits twist in a clockwise fashion towards the right. Left-handed bits, however, turn counterclockwise towards the left. These bits were originally designed back when power drills didn’t have reverse functions requiring nothing more than a flick of the switch to set— it was easier to use a left-handed bit rather than set the tool to reverse manually.

Today, left-handed bits are still sometimes used for removing bolts or other fasteners that have broken off inside the hole, making them very difficult to remove by hand. By drilling slightly into the broken fastener with a left-handed bit, you can often loosen the broken screw enough to pull it out and remove it.