1 / Select locations
There are plenty of locations where you can add fan mounts to your case, but they’re most easily created on flat metal panels, such as rooves or bases. Mounting extra fans in these areas can also benefit graphics card and CPU cooling.
2 / Check clearance
Before cutting your blowhole, check for clearance on the inside your PC, to make sure your fan won’t clash. Check for motherboard heatsinks in the area, as well as reinforcement beams inside your case, which you’ll want to avoid cutting if possible.
3 / 120mm vs 140mm fans
If you have the space, you don’t need to stick to 120mm fans and can consider 140mm fans instead, which usually offer lower noise levels and higher airflow than their 120mm counterparts. They’re the same thickness as 120mm fans, but are wider and longer, so check you have enough room.
4 / Types of grilles
If your fan is exhausting air from your case then you don’t need to worry about filters. However, it’s always a good idea to protect yourself and others from fan blades using a grille. These are cheap, and you can opt for snazzy designs or even 3D-print your own ones.
5 / Dust filters
If your fan will be acting as an intake, then you need to use a dust filter. There are a few options here, and the easiest is using an off-the-shelf filter that fixes between the fan and mount, or you can use a magnetic filter that attaches to the outside. You can also create your own filter using a material such as nylon tights or thin cloth.
6 / Mark up for cutting
Use masking tape to draw your blowhole position. This tape will also protect the case if your saw blade slips. Mark the spot for a pilot drill in the centre of your fan mount. We’ll be using a 114mm hole saw to create our fan blowhole, with a pilot drill mandrel.
7 / Drill pilot hole
Allow the pilot drill to create its guide hole. Do this gently, as it’s easy for it to slip at first, which will result in your hole being off-centre. Once it’s passed through the panel, lift the holesaw away and check that the pilot hole is lined up for the holesaw to make its cut in the right place.
8 / Option 1: use holesaw
The holesaw will cut a single large chunk out of your case, but it can be tough to cut through steel cases, so take your time. Apply medium pressure with the saw but, when you’re nearing the end, back off the pressure and allow the weight of the drill to do the work.
9 / Option 2: Use a Dremel
If you don’t have a drill, you can mark out a circle for your fan blowhole and gradually work a Dremel with a reinforced cutting disc around the hole to cut it out. This will take much longer than a holesaw, and will need more finishing work, but will save on the cost of extra tools. Make sure you use mask and eye protection.
10 / File edges
Use a rounded metal file (Ed: with less rust on it! than Antony's one!) to get rid of sharp edges around the hole, and continue filing until the edges are smooth. Alternatively, you can also use a Dremel and sanding attachment.
11 / Colour the edges
If you have a black case, you can use a permanent marker pen to colour the bare metal. This will make your cutting work look far less obvious than with the bare silver metal on show from its meeting with the saw.
12 / Mark up drill holes
With your hole cut, line up your fan and use it as a template to drill your fan-mounting holes. The screws just need to pass through the panel, so use a drill bit that’s slightly larger than the screws included with your fan.
13 / Drill screw holes
Go ahead and drill the mounting holes into your case, checking the alignment of each one first to ensure that they all line up. If one hole ends up being slightly amiss, you can use a small metal file to open it in the desired direction and the screw head will usually cover the oversized hole.
14 / Install filter or grille
Now go ahead and install your filter or fan grille, ensuring it’s the right way around. Grilles usually sit on the outside of the case, while some filters are best placed between the fan and your case’s panel.
15 / Install fan
If you’re installing the fan in the base of the case, flip it upside down to make the installation process easier. Hold the fan in place from underneath, then insert the mounting screws. Don’t tighten one fully, but instead move around and tighten each screw a few rotations in turn.