A-Z guide for Drilling Aluminium

Aluminium is a low-density and non-ferrous metal that is resistant to corrosion. It is also soft and ductile, which means some challenges involved when drilling aluminium. This is because its unique characteristics can cause it to have more constant and prolonged contact with the cutting tip, causing heat to build up. 

The melting point of aluminium is 660 degrees Celsius. Since it has a low melting point, drilling must be done as efficiently as possible to avoid overheating. If not, the aluminium parts in direct contact with the drill bit can melt and stick to the surface. 

Drilling aluminium should run smoothly, as long as you follow a few simple guidelines. 

How to Drill Aluminium

It is essential to follow basic guidelines and techniques to prevent damaging aluminium. To help you drill into aluminium safely, take a look at our step by step guide:

Drilling should always be done safely, therefore it’s important that you wear the correct safety equipment. To avoid metal shards getting into your eyes, you should always wear eye protection, such as safety goggles. If possible, wear gloves to protect your hands while drilling. 

Use a marker to locate the exact position of the hole. This will ensure that your drill bit and centre punch are positioned precisely where they need to be. In addition, using this method will prevent any errors in locating the holes.

When you initially start drilling, drill bits tend to wander. Using a hammer and centre punch, pound a small indentation into the surface where you want the hole to be. This dimple will help guide your bit as you begin to drill. You should also use a clamp to hold down the metal you're drilling so that it does not move around and cause an accident.

There is a risk of overheating if you drill too quickly, so it’s vital that you keep an eye on your speed at all times. The drill bit's size should be considered when determining how fast or slow it is to drill into aluminium. The smaller the drill speed, the quicker the RPM should be.

When drilling aluminium, use a reasonable amount of pressure. Keep in mind, excessive pressure should be avoided since it causes heat to build up and may melt the area in direct contact with the drill bit.

Peck drilling helps to split the chip into smaller pieces, making it easier to remove them from the machine. Begin "pecking" when the hole is four diameters deep. First, you must drill a small amount and then pull the drill bit back to release materials to complete the hole. You should do this several times until a hole is formed in the aluminium. 

To make drilling more manageable, you should apply an adequate amount of lubricant to the drill bits. You can use cutting fluid or a multi-purpose oil for this. This will help reduce friction and prevent a build-up of heat. 

What Is The Correct Drill Speed for Aluminium?

The cutting speed for aluminium will differ depending on the bit size used. However, on average, you need around 140 - 300 FPM for aluminium alloys. 

The size of the drill bit and the cutting speed of the material are the factors that influence the RPM setting. A larger drill bit will require fewer revolutions, while a smaller drill bit will require more rapid revolutions. 

The below table sets out the cutting speed for different types of aluminium alloys:

To calculate the RPM, you should follow this simple formula:

RPM = (Cutting Speed  x 4) / Diameter of the cutter

Example : 

Cutting Speed = 200 fpm

Diameter of Drill bit = 0.5

RPM = (CS x 4)/D = (200  x 4)/0.5 = 800/0.5 = 1600

For example, if you have cast-treated aluminium and have a 0.5 diameter drill bit, you need at least a 400 RPM drill speed.

Best Drill for Aluminium 

To avoid damage to aluminium, you can select one of the following drill options:

Hand Drill

It is possible to use a hand drill to make a hole in aluminium, however one of the difficulties of using a hand drill for metal is putting the hole exactly where you want it. Utilizing a centre punch is an excellent solution and before using your hand drill, you should drill a pilot hole. You can then increase the size of your drill bit gradually or, for instance, 1/8", 1/4", 1/8", and other sizes as required.

Drill Press

You should use a drill press when drilling aluminium plates more quickly and more accurately. Before drilling, you should use a hammer and centre punch to mark the hole. Then, check if the holes you've marked out are in the proper spot. You'll need a 2.5-3mm drill bit to begin drilling the pilot hole. 

Best Drill Bit For Aluminium

To help you choose the right drill bit for aluminium drilling, here are some of the most common choices:

High-Speed Steel (HSS) 

High-Speed Steel (HSS) is used in drill bits because of its increased hardness and wear resistance. These properties allow for faster drilling and are suitable for more rigid materials.

Titanium Nitride 

Titanium nitride, or TiN, is a corrosion-resistant metal used to coat HSS drill bits to increase surface hardness. You can identify titanium nitride by its vivid gold colour. Compared to HSS, titanium-coated drill bits can drill through tough materials six times faster. 

Cobalt HSS

Cobalt High-Speed Steel (HSS) drill bits contain Cobalt, which increases the material's toughness. Cobalt boosts steel's strength and heat resistance

Titanium-Aluminium-Nitride (TiAlN)

TiAlN coating is a versatile coating that is made up of titanium, aluminium, and nitrogen compounds with a coating thickness of 1-4 micrometres. It also features a heat and oxidation resistance coating which speeds up cutting and work processes.

Carbide

Carbide has a lifespan that is ten to twenty times longer than a cobalt drill bit. Therefore, Carbide drill bits are suitable for hard substances.

So, which drill bit is the best for aluminium drilling?

A regular HSS drill bit can be used to drill through aluminium because it is a softer metal. However, a cobalt drill bit would be preferable due to aluminium's low melting point. In addition, the cobalt drill bit will help the heat evaporate quickly and will therefore prevent overheating. 

Here are suggested drill bit materials and coatings for different aluminium alloys.

Choose The Right Drill Bit for Aluminium Drilling

To ensure you choose the right drill bits for aluminium drilling, take your time and look through our assortment of drill bits and accessories. RUKO Shop UK carries a variety of drill bits for aluminium, so you can complete your project safely and quickly.

Feel free to reach out to us if you have any questions or concerns, and we'll be happy to assist you.