How to Drill Holes into Metal

The first thing you need to consider when drilling holes into metal is the type of metal you’re working with. Different metals have different properties, meaning you will have to adjust the process depending on what you’ve chosen. Let’s look at some common types of metal and their properties:

Steel – Steel is one of the most common metal construction materials. It’s tough and durable, making it a great choice for many projects. Steel requires you to use drills that are designed for hard metals. Selecting the wrong drill can mean you’ll struggle to create holes and possibly damage your drill.

Aluminium – This is one of the softest metal types you can find for construction. It’s a much easier metal to drill because of its lightweight and flexible nature.

Brass / Copper – Both of these are also soft metals that are easy to drill. However, it can be tough to get even holes with these metals because they can grab at the drill bit.

Cast Iron – Cast iron is one of the more brittle metal types, and as such can be difficult to drill. You’ll need specialised bits (such as carbide or cobalt) and plenty of cutting fluid to reduce heat and friction.

Once you have considered the type of metal you’re working with, it’s time to choose the right drill for the job. The type of drill you choose is important to ensure you drill a hole in metal with precision and safety.

Drill types

Corded drills – Work with a consistent power supply and are perfect for heavy-duty tasks. If you’re working on a project involving many holes or working with tough metals like steel – a corded drill would be your best choice.

Cordless drills – Convenient and portable, but they won’t always offer the same level of power. Keep in mind that many cordless drills are now designed with high voltage batteries, allowing you to handle many metal drilling tasks. Cordless drills are better suited for lightweight metals like aluminium or copper.

Advanced drill options

Pillar drill – A pillar drill provides precise and stable drilling. They are capable of handling larger bits and tougher materials. The main disadvantages of these drills is that they are not portable and require more space.

Magnetic Drill – Magnetic drills are specialised pieces of equipment that are excellent at drilling into large, stationary metal pieces. Their magnetic elements make them very stable. Keep in mind that magnetic drills are expensive, heavy and much less portable than other drills.

Drill power

You should also consider the power level of your drill. Higher voltage means more power. If you’re working with tougher metals, you should choose a more high-powered drill.

Drill bits

Next up, it’s time to choose the right bit for your drill. A ‘bit’ here refers to the end of the drill – the metal component that will do the actual drilling. There are a few drill bits you can choose from, depending on the metal you are working with. Consider the following:

High Speed Steel Bits – Sometimes abbreviated to HSS, these bits are made from a special type of steel that can withstand high temperatures. They can be used on many different metals, from mild steel to aluminium. These are durable and widely available – a good choice for your metalworking project!

Cobalt Bits – These are made from an alloy of steel with a low percentage (5-8%) of cobalt, which helps to increase their durability and heat resistance. Cobalt bits are a great choice for tough metals like cast iron or stainless steel.

Titanium coated bits – Made from HHS with a titanium nitride coating, these bits are perfect for drilling jobs where you need to reduce friction.

Now that you have decided on the best tools for the job, it’s time to get drilling. But first, you’ll need to protect yourself. Drilling holes in metal causes shards to fly off from the hole – this means you’ll need eye protection.

Safety glasses are the common way to safeguard yourself. You should also consider your clothing. Remove or protect anything that could get caught in the drill and cause an accident, for example, loose clothing or long hair.

Always remember to clamp your metal before you begin drilling. Fail to do this and you run the risk of your drill spinning the metal around and causing potential injuries to yourself. Use as many clamps as you need to keep it safe and secure. Double-check that these clamps are in place before you drill.

You’ll want to make an indent in the metal. This is to ensure that your drill doesn’t slip off when you first start drilling, damaging other parts of the metal you’re working on – or worse, yourself! Create a small dimple in the metal where you want the hole to be, this will help you create a precise hole.

Now it’s time to start drilling. When drilling, remember to begin with a slow rotation speed. This is especially important for hard metals like steel. You should aim to drill as slowly as possible, as this will reduce excessive heat and stop your drill bit from dulling.

After each hole, make sure you check that the metal is sufficiently clamped. Always remember to keep safety your top priority.

You should also clear out the drill hole after the drilling is completed. This is a process called ‘deburring.’ There are specific deburring tools you can purchase for this, allowing you to grind away any burrs and create an even, fit-for-purpose hole.