A Guide to Drilling Aluminium

Drilling aluminium can be a little more challenging than many people assume. This metal is fairly soft, with a low melting point. Because of this, you will need to avoid overheating if you want to prevent the risk of melting aluminium from sticking to your drill bit. The softness of the metal poses another challenge, which is prolonged contact with the cutting edges of drill bits. This metal is more likely to form chips when drilling, which is yet another common challenge to look out for when you are drilling this type of metal.

Despite its challenges, drilling into aluminium is a lot easier when you use the right drill bits, method and guidelines to navigate these common issues. In this guide, we’ll share some tips that will make it easier to drill clean, smooth holes into this sheet metal.

How to Drill Holes in Aluminium

Here’s what you need to know before you drill holes into aluminium sheets.

Use the right drill bits

For small holes, you can use twist bits such as a standard metal HSS bit. These can be used to first drill small pilot holes and then gradually enlarge the holes until you reach the size you want. This bit is a good choice for small holes or individual holes. It can take a bit of time, however. For larger holes or multiple holes, this isn’t always practical. A better option for bigger holes is a metal HSS step bit. These bits have 12 sizes in a single bit, giving you far more flexibility when creating holes. They create smooth, clean holes without the risk of chips, unlike twist bits, which will need to be cleared of chips as you drill.

Use a slower drilling speed

With a soft metal that has a low melting point, you will need to watch your drilling speed very carefully. Drilling at a high speed will increase the risk of overheating. As we briefly mentioned earlier, this can be a disaster. The last thing you want is melted metal all over your workpiece. Hot, melting metal is a safety hazard, too. Drilling at slower speeds will prevent chips as well. If you are using a twist bit, you will need to drill slowly enough to allow the drill to work without a build-up of chips. 

Use lower pressure

You don’t want to force your bit through the sheet, either. Using excessive pressure when drilling a soft, low-heat metal will do the same thing as using excessive speed. You will end up with ragged holes, chips getting stuck in your twist bit and an increased chance of heat buildup. Instead of forcing the bit through the sheet, work slowly, at a steady pace.

Use lubrication and coolant

When drilling this metal, it is essential to use lubricant and coolant to prevent overheating. The temperature should always be kept down to prevent friction and melting. You can lubricate your bit by placing a wet sponge just below the bit as you work or by using oils, sprays or other products made specifically for this purpose. 

Use protective gear

Power tool safety is something you cannot afford to overlook. You should always wear safety gear - whatever material you are drilling. As it is a soft metal that is prone to chipping, you will need eye protection in case small particles are released during drilling. It is imperative that you clamp the sheet down when drilling. This metal is soft and can easily move if it’s not secured properly. The low melting point of the metal also poses a risk, so you’ll need to wear gloves when working with this metal as well.