How to Drill Holes Through Metal the Right Way

by Raymond Archambault
person holding drill machine

You don’t often have to drill into a piece of metal for a DIY task. Typically, you drill pieces of wood or stone. However, at times, you may need to drill a hole in various types of metal such as aluminum or cobalt steel in which case you want to complete the task without any damage.

Fortunately, there’s a technique, which if followed properly, drilling metal becomes a walk in the park. The secret is to keep the drill bit cool. In this guide, we’ll delve into everything you need to know on how to drill through metal by keeping the drill bit cool.

What’s the Best Drill Bit to Use?

For drilling aluminum, twist drills are an ideal option. They are best suited to drill metal.

How to Choose the Best Twist Drill Bit

Before you start drilling, it’s important to understand that the material of the twist drill bit plays a key role. Standard twist drill bits are constructed from black oxide, high-speed steel (HSS), titanium, cobalt, and tungsten carbide. Of these materials, tungsten carbide is the most potent, priciest, and used to drill stainless steel. Tungsten carbide drill bits are perfect as they get the job done efficiently and are more durable than other materials.

Secondly, let’s discuss a few factors to remember when choosing the perfect twist drill bit.


Check out the tip of the bit and notice whether it contains relatively flat cutting edges but lacks a protruding center point. Drill bits with center points come in handy for drilling wood, so using them to drill metal ruins not only the project but also the bit.

A Step Drill Bit

It also gets the job done of drilling thin plate metal. A step drill bit is cone-shaped and comes in a wealth of sizes.

Desired Hole Size

Depending on what you’re objective is, you may want to drill a small hole or large holes. Select a drill bit that matches the size of your desired hole. However, if you’re uncertain of the ideal size, choose a drill bit that’s 1/64th inch bigger than your desired hole size.

Drill Machine for Drilling Metal

Now that you’ve chosen the most suitable bit for your hole you need a drill. That begs the question, which drill is best suited for drilling metal? Any power drill machine will get the job done perfectly.

Safety Measures When Drilling Through Metal

Here are a few pointers on how to drill through metal safely.

  • Before drilling, wear safety goggles to protect your eyes from curly, sharp, and tiny metal shavings – this is especially important when drilling through sheet metal. These are hazardous to your skin and eyes. But, compared to your skin, your eyes are more sensitive. You can lose your eyesight if metal shavings get into your eyes.
  • Wear heavy leather gloves when drilling through metal.
  • Firmly hold the metal you’re trying to drill. Clamp the metal securely to prevent it from spinning or moving as you drill through it. When drilling, the spinning force of the machine is transferred to the metal, causing it to move or spin. The sudden motion of the metal sheet can trigger an accident. Therefore, besides wearing safety goggles and gloves, clamping the material securely is equally as important.
cordless drill

Source: Unsplash

How to Drill through Metal

To get started, you’ll require the following items.

  • Lubricant oil
  • A sacrificial board
  • Safety glasses to protect your eyes
  • A hammer and center punch
  • Heavy leather gloves
  • A power drill with the appropriate drill bit

With the items required, follow the steps below.

  • Position the board on both sides, under, or over the metal you want to drill. You’ll have to drill over the board. To drill through thin metal then clamp it over the board to prevent the drill bit from tearing up the hole. Keep in mind, plywood, MDF, or particleboard is equally as effective. For a clean hole, clamp a sacrificial board over the thin metal.
  • Drill bits will wander off immediately when you start drilling metal. Wandering while drilling can result in an accident and ruin the project. Therefore, before using the drill bit, mark where you want to make the hole using a hammer or center punch.
  • Now it’s time to add the lubricant Note that drilling through metal generates immense friction, making the drill bit heat up fast. To prevent heat and friction, add a few drops of the cutting fluid before drilling. You can use motor oil, cutting oil, or household oil. If you’re drilling a big hole, you’ll need to use the oil various times. It boils down to using adequate oil to keep the drill bit cool.
  • Now begin drilling with the bit that’s smaller than your desired hole. We recommend drilling using a small bit at first to quicken the process. For instance, if you require a ¼-inch hole, begin by using an eighth drill bit, slowly working your way to the ¼-inch counterpart.

Tips for Drilling Through Metal

Here are a few pointers to keep in mind.

  • Drill with low pressure and slowly. Always run the drill at a slower or half speed. Drilling too quickly heats the drill bit
  • If the drill bit is big, reduce the drilling speed. Therefore, the bigger the drill bit, the slower the speed required.
  • If you notice smoke, that means the drill is overheating and it’s your cue to stop drilling and give the drill bit time to cool off before adding lubricant The presence of smoke means you’re using inadequate lubricant and drilling with excessive speed and pressure. Once the bit cools and you add the oil, proceed to drill with low pressure and speed. Tip: if you notice this happening more often than not, check to make sure you’re not using high-speed steel bits.


Let’s discuss the answers to some of the most commonly asked questions about drilling through metal.

1. Will your drill become dull if you drill through metal?

Yes! There’s a likelihood of your drill becoming dull when drilling through metal.

2. What causes the dullness of the drill bit?

The likelihood of your drill bit getting dull is because when drilling through metal the sturdiness of the material causes the dullness if you drill too quickly. However, if you drill through the metal at a low speed with low pressure and use the lubricant, your drill bit won’t dull.

3. What should you do if your drill bit becomes dull?

You can always re-sharpen your drill bit when it gets dull.

4. How can you make a hole through metal?

It’s advisable to drill through metal using the lowest possible speed using a suitable drill bit. Steel and other hard metals, in addition to bigger drill bits, call for slower speeds. With a small twist bit ranging from 1/16 inches to 3/16 inches, you can drill through most metals at 3,000 revolutions per minute (RPM).

5. Why can’t you drill through metal?

Drilling through a hard surface calls for the use of specialized drill bits. The standard counterparts are not designed for metal, so they wear out prematurely. Therefore, you require hard bits that can drill into any metal without succumbing to damage.

6. Which type of drill bit can pass through metal?

A titanium drill bit is a high-speed steel (HSS) counterpart with a layering of titanium oxide. It’s corrosion-resistant and sturdy. It’s also more durable compared to regular HSS bits and is perfect for drilling through metal sheets and all metals.

7. What’s the strongest drill bit for metal?

Cobalt drill bits (HSCO) are regarded as an upgrade of HSS bits because 5% to 8% of cobalt is blended into the base material. It’s an excellent option for drilling into harder steel and various grades of stainless steel. Carbide is the sturdiest and more brittle of the various drill bit materials.


Now that you know how to properly use your power tools you can use a cordless drill or hand drill to properly drill a lot of holes into almost anything! Remember to always start small when metalworking, and that it boils down to keeping the bit cool. That entails using enough lubricant while drilling slowly at low pressure. It’s a straightforward yet effective technique.


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