Thar She Blows!

Posted 07/20/2007 at 4:59pm | by

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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!

Time for the fun. It’s best to drill the center (pilot) hole first. You can either use a different bit of the same size, or simply pull the saw off the hole saw assembly and use the arbor bit. This way you can see what you are drilling. Your drill should be set to “clockwise” rotation. You will need only enough pressure on the drill to control it. Start slow until you have a divot, and then speed up the drill to about half max. Let the bit do the cutting.

Once you have your pilot hole, the rest is pretty easy – just cut the hole with the saw. Use a moderate speed and don’t push on the drill. Let the saw do the cutting. In fact, the weight of the drill is often too much pressure, so you may find yourself pulling it back. If you stop or the saw jams, simply pull it away from the cut, start it spinning again, and then begin cutting again. If you have never used a hole saw before, consider practicing on a piece of (well secured) scrap wood.

Pretty easy. Take a look into the case and you’ll know why you don’t do this on an assembled computer – that’s not dust – one of those little shavings on a motherboard could cause all kinds of trouble. Now you just have to dress up the hole. The edges will be very sharp and may have metal splinters or burrs (ouch) so be careful. You can use a piece of sand paper (wear a thick glove) or an attachment on a roto-tool for the job. Oh…and despite the temptation, leave the tape on until you are completely finished.

An thar yare. One blow hole matey.

Next time I’ll install the fan “8-hole style”, show you a trick or two with the drill, and talk about that ever flame war starting subject of which way the fan should blow - depending on where the hole is.

Happy Moddin'!

And keeping with the “how to” theme, today’s bling is one of the best guides I have ever seen. It’s absolutely riveting!