I don’t know why beginning (and even some experienced) modders approach installing a blow hole with such trepidation (that’s fancy for “fear”). I think part of it involves the cutting of a perfect circle through metal. I’m sure it also doesn’t help that there are 6 ways from Saturday to do it. I’ve seen folks attempting or recommending every tool from a Dremel to a type of reciprocating saw referred to as a “saws all” (um…u no try pls thx). I appreciate originality and all, but sometimes a tried and true method is best - and that method would be the hole saw. It’s actually quite an easy mod to do with the right tools.

Oh, a little EULA first if you don’t mind:
Any safety reminders given herein are not to be taken as a substitute for proper training and, if required, supervision. You (the reader) are solely responsible for any outcome, positive or negative, resulting from use of this information.

Now, let’s get to the hole cutting business! I’m only going to cover making the hole in this post so I can give a bit more detail. I’ll get to mounting the fan and my patented (not really) 8-hole mounting technique next time. You will need some easy to acquire tools for making the hole cut:

• Variable speed drill (preferably a cordless type)
• Permanent marker
• Masking, drafting, or painter’s tape
• Hole saw with bit/arbor/jig (if required)
• Eye Protection
• Measuring device (a ruler will work, a square is better).

You can get all of these at your local DIY home center and they can be used for many projects of the modding kind (computer or otherwise). Real tool talk deserves its own exclusive post at some later date, but I do need to address the hole saw mentioned here - in case you’re running out to buy one.

You want to make sure the hole saw is the right size. Fans are often measured in millimeters (and to the outside of the casing) and holes saws are often measured in a far superior form of measurement - the inch. Here’s a handy table for convertin’ fan size to proper hole saw size:

50mm = 2.25”
80mm = 3.0” (3 1/8” if you can find it)
92mm = 3.5”
120mm= 4.5” (4 5/8” may also work)

Most important, make sure that the saw you buy or use is labeled “multi-purpose” or “for metal and wood”. Bi-metal saws are best. Some hole saws are only made for wood – you don’t want to use those. You also want to do a bit of research. Hole saws are all of similar design, however, some are far better in quality of materials than others. Further, the arbor and bit (sometimes called a jig) are typically interchangeable among different hole saw sizes – but only within the same brand and series! That means, you will want to stick with a brand – it will save you money in the long run. I’m not going to recommend a brand, but I will say that I use Lenox and am happy with them, and you should expect to pay more than $10 USD for the size we are using here (meaning that the one you’re looking at for $3.99 right now is not the one you want - heh).

Once you have your tools ready, pull the components out of your case (or the part of the case you are going to cut if it’s removable). Cutting a hole into a fully assembled computer is asking for damage. With the case empty, find where you want to put your hole and measure off to mark the center. Keep in mind that components will eventually be in the case. If the hole is on top, for example, make sure you will have room to install the fan while both a PSU and a top bay mounted optical drive are in it. Once you have the center spot marked, you will want to put tape anyplace the blade of the hole saw will cut through. This will minimize any scratching if you slip. Finally, make sure the case is secured somehow and won’t move while you are drilling/cutting. Put on your safety glasses!