19 inch computer rack · Mar 9, 06:29 pm by Max
Update: New photos (see bottom of page)
It's (nearly) every techie's dream to have their own 19" computer rack. I have now built my own and will show you how to build yours ;D
The simple idea is this. A basic 19 inch rack is simply a box. The internal width is 19 inch, and the height goes up in 1.75" increments. (1U [unit] is 1.75 inches high, therefore if you want to house 2U, you need to make the internal height 1.75×2 = 3.5"). I chose to make my box in wood; it shouldn't overheat as only one computer is going to be stored in it and it has ventilation grills at the sides.
Step 1 - Cutting the Wood
The first step is to cut four pieces of wood. There are two (three?) ways of cutting them so that they glue together. The first is simply to cut the wood at a 45 degree angle and glue it together so that the whole angle is 45×2 = 90* (which is what we want). The second way (which I don't recommend, for reasons of stability) is to cut the wood simply with 90 degree angles and stick it together. The third, and best way, is to cut rebates (more about this in Step 2).
Step 1: Two pieces of wood straight from the saw - please note you need to cut two of each (only one is shown for clarity)
The value of d is the depth of your rack. To find this, take the longest (deepest) appliance you are going to place in your rack, and add 10-20cm onto it.
The value of w is 19 1/8 inches (the 1/8 is added so that the appliance will fit in without any problems (it won't become too big), added to twice the thickness of the wood you are using, which in my case is 18mm MDF. This is due to the nature of the box cuts we're going to do in Step 2. If you are using 18mm wood, w should be 51.9 cm long.
h is the internal height of your rack, added to one times the thickness of the wood you are using. Not twice the thickness, only once. This is, again, due to the nature of the box cuts (they only go through half of the wood). Here's a little table with the number of units (U) you want to make your rack, the internal height in inches, the internal height in mm, and the value of h if you use 18mm wood.
| Units | Internal height (in) | Internal height (mm) | h (mm) |
| 1U | 1.75 | 44.45 | 62.45 |
| 2U | 3.5 | 88.9 | 106.9 |
| 3U | 5.25 | 133.35 | 151.35 |
| 4U | 7 | 177.8 | 195.8 |
| 5U | 8.75 | 222.25 | 240.25 |
| 6U | 10.5 | 266.7 | 284.7 |
| 7U | 12.25 | 311.15 | 329.15 |
| 8U | 14 | 355.6 | 373.6 |
| 9U | 15.75 | 400.05 | 418.05 |
| 10U | 17.5 | 444.5 | 462.5 |
| 11U | 19.25 | 488.95 | 506.95 |
| 12U | 21 | 533.4 | 551.4 |
| 13U | 22.75 | 577.85 | 595.85 |
| 14U | 24.5 | 622.3 | 640.3 |
| 15U | 26.25 | 666.75 | 684.75 |
| 16U | 28 | 711.2 | 729.2 |
| 17U | 29.75 | 755.65 | 773.65 |
| 18U | 31.5 | 800.1 | 818.1 |
| 19U | 33.25 | 844.55 | 862.55 |
| 20U | 35 | 889 | 907 |
Step 2 - Cutting the rebates
The next step is to cut all the so-called "rebates". These are square cuts spanning all the way along one edge of the wood, going halfway down the thickness of it, and as wide as the piece of wood which you want to glue to it (18mm, in my case). This can either be done by lowering a circular saw to the depth desired, then cut in 5-6 "goes", adjusting the saw by 3 or so millimeters each time, to cut a thick groove. Another way is to use a router. This should be done on 2 parallel sides of each of the 19" by 19" pieces of wood.
Step 2: A closeup of one of the rebates
Step 3 - Assembly!
The assembly is fairly painless. Spread glue on the inside of the rebates, then place the two larger pieces into the rebates on one of the smaller pieces. Then, place the remaining smaller piece on top, and clamp the whole thing together. While waiting (at least 4 hours, depending on the wood glue) for the glue to set, you can get on with Step 4.
Step 3: The assembled main framework of the box.
Step 4 - Rackstrip
For this step you will need two equal lengths of rackstrip (or rack mounting rail). One website which stocks rackstrip is Maplin. They are a widely established electronics shop in the UK, but I have never bought that particular item from them so I don't can't comment on construction quality - if anyone does decide to buy from them, feel free to comment on your experiences here and I'll edit the article accordingly.
All you need to do is cut two lengths of rackstrip, both equal to the internal height of your rack which you decided in Step 1. (This is the internal height, not h.)
Be careful, though! You can see from the picture that the holes have a different pitch (small gap, large gap, large gap, small gap, large gap, etc...). You must make sure that the pitch on both of the strips are the same. And since they are going to be mounted opposite to each other, cutting 2 identical pieces rackstrip isn't going to work - you need to make sure the second piece you cut is a mirror image of the first piece.
Step 4: A closeup of the rackstrip.
Step 5 - Mounting the whole thing
The first step is mounting the rackstrip. If there aren't enough holes, you might want to drill some more in the rackstrip and mount them. Depending on what you are planning to mount, you might want to drill more or less holes - 1 hole every 20cm is more than enough for lightweight usage.
You'll then want to actually mount it. As long as the rack is symmetrical, they can be mounted anywhere (I decided to mount mine so that the front of the strip was 1" back from the front of the rack).
The next step is to cut ventilation holes if needed. Drill holes and cut through with a jigsaw to make rectangular (or other-shaped, if you feel rebellious) holes, which can optionally be filled in with wire mesh.
The last step is to place a cover on the back. Cut a cover the right size (i.e. the internal dimension + twice the thickness of the wood). Cut a hole in it for cables if you need to, and glue (or nail it on). If you are going to wall-mount your rack, you will need to cut blocks and screw them in.
Step 5: The "finished" rack.
Final Touches
There are many things you can do to improve your basic rack. One such thing is to cut four thin cuboid "rods" of a good wood such as pine at 45 degree angles, and stick them on the front of the rack, or you could also create a hinged door. But one fairly cheap (yet effective) modification if you are using faced MDF, plywood, or nearly any wood apart from standard MDF, is to get yourself a can of teak oil. This will slightly darken the wood, and add a "professional" look to your rack, as well as protecting it from water spills, etc...
I hope you found this tutorial useful. Please, please, comment on it if you enjoyed it (or didn't!) by clicking the "Comment on this article" link just underneath this paragraph (or filling in the form if it is already there). Happy rack-building!
I've had these photos for some time now but have only just got to uploading them. If you are using Firefox, the better browser ;), you can right-click on any of the images and click "View Image" for a better look (as with any of the illustrations)
Photos of my rack:
thanks – looking forwards to the pics
— mark in canada Dec 31, 01:35 am #
Have you seen this site? (link below)
Reply from Max:
Yes, I have - not before I created this article though. It seems that both ways have their merits - but I have focused more on building the actual box & joints etc... (going into much more detail than you have) but omitting the finishing touches such as doors, painting, wooden frames, mounting, etc... basically, I am expanding on the sentence "building the case was easy". :D
— http://rack.modzone.dk/index.htm Jan 6, 09:06 am #
Max, Very nice construction. But a cautionary note: Heat is the enemy of all electronics. It’s a bit difficult to tell from the graphics, but if the back of the rack is closed, heat dissipation will be a problem and shorten the life of any rack-mounted equipment therein.
73 de Mike, K6MKF
Reply from Max:
Heat dissipation was indeed one of my main concerns when building this rack; if I were housing four power-hungry Pentium 4 computers in there I would definitely have built it out of metal; and even though the only real heat generating equipment I will be housing in there are a PII computer and a 400W amplifier, I did build two ventilation strips along the sides (as you can probably see from the 'photo)
— Mike Flowers Mar 2, 01:12 am #
that’s amazing man!
Reply from Max:
Thanks! Glad to know you enjoy it ;)
— bary May 3, 03:14 pm #
Very, very helpful article, thanks for the guidance! gonna try building this straight away :D
— Kevin in the UK May 21, 12:50 pm #
Max – Nice article. One comment – the “box joint” you describe is usually called a “rabbet” (USA) or “rebate” (UK) (see en.wikipedia.org/wiki/Rabbet).
A “box joint” is usually taken to mean an interlocking set of ‘fingers’ – see: en.wikipedia.org/wiki/Box_joint. (The latter looks like a lot of work, but is very strong and actually quite simple to make with a simple jig.)
The face frame (‘cuboid rods’) is a nice touch – typical in kitchen cabinetry to conceal a plywood edge.
One other neat suggestion – paint the case with a “hammered” spray paint, available (over here, anyway) at any hardware store in steel- or dark blue, grey, copper, sea-green, and other colors. Looks like hammered metal – very sharp. Or, for another very neat “WWII” look, many auto shops and some paint shops sell a “wrinkle-finish” paint that looks like the finish on old binoculars or cameras.
There’s an example of the hammered blue finish on my website (url attached), where I detail the lathe I’m casting and building from scratch, which one can build using only hand- and a few basic common power tools. Enjoy!)
Cheers!
Andrew
Reply from Max:
Did I say box joint? I mustn't have been thinking then. :P Thanks for pointing that out! I've seen the 'hammered metal paint' around and (judging by your photos anyway) it looks pretty nice! I might go down and buy a can to see what it looks like. Oh, and how much is that lathe costing you in materials?
— Andrew in Silicon Valley Jun 19, 03:39 pm #
Very nice :)
Will most probably use this design if I ever get my hands on some rackmount equipment. At the moment I’ve just got servers with different sized cases :x
— pepolez Jul 1, 02:44 am #
Is there a reason you closed off the back? I’d think with something like this it’d be better to have easy access to the back ports without too much fuss.
Reply from Max:
Yeah, I've actually removed the back now both for better heat dissipation and for better access to cables as it is standing up against a wall - though if you had it on a desk facing a door (as I'd originally planned it to be), for example, you might want a back on it for aesthetical reasons.
— Jon Jul 31, 10:28 am #
Hi Max,
I saw your rack and want to build one. I like the rack rail you used in yours. You mentioned that Maplin sold rack rail but I could not find any rail at Maplin that looked like yours. Where did you get your rail?
Thanks,
John
Reply from Max:
Hi, John. Maplin's rackrail is order code N84AA, (here's a link). At first glance, the page may look like it's selling a set of nuts and bolts, but you need to hover your mouse over the small thumbnail of the rackstrip to the left of the photo to get a clearer view.
Hope this helps,
-M
— John Nov 11, 03:38 am #
built my own rack using your guide, turned out great! thanks
Reply from Max:
Great! Do you have any photos of your rack? Email them to me, and I'll be more than happy to post them here...
— Lukas from Vancouver Canada Dec 6, 06:41 am #
out of wood? are you nuts?
— j Feb 11, 08:22 pm #
I have made many racks using ‘rack strips’ for radio studio equipment, I setup the items I need installed and build the box custom, usually painted black. It works very well, though it does take time and time is money, sometimes its cheaper to buy it. Shipping kills us here in Hawaii so building is often better. By the way great score by being on Wikipedia, its a real resource.
— john bruce Jun 11, 06:36 am #
All I can say is… Nice rack! ;) I would like to build one eventually, and organize some of my network gear… The rack rail was my main concern, but you had some other nice ideas! Thanks!
— Don McMorris Jul 3, 06:40 am #
I built a rack using the rail from Maplin-It was very good quality, although a little dusty!!! This site is worth a look:
http://www.flickr.com/photos/cjw333/29627416/
— David Weight Aug 22, 12:16 am #
Just a problem when we say 19’’ of large : is it the width of the machines ? or internal width of the box ?
Anyway, your explaination is great and your boxes too ! Good work man ! Greatings from france !
— Charlotte Oct 17, 12:25 pm #