4Ux2 Computer Desk

The original driver for this project was a small annoyance - my current computer desk's keyboard drawer was too shallow, so I couldn't use a gaming keypad (Razor Orbweaver style). So I aimed to make a nice deep keyboard drawer, and as a bonus - a desk to put it in.

Other, design issues to solve were:

• Having multiple computers close enough to be useful for KVMs (keyboard,
  video, monitors switches), with convenient power, network and USB charging outlets for staging electronics projects (this is a working desk).
• Being moderately safe from a three year old who likes disconnecting disk drives and putting his cars in the array instead (this dictated type of computer cases, and placement of power buttons).
• Allowing for the desk to be mounted as a standing desk, or on legs - so self contained and strongly built.
• Not occupying too much more space than a 'normal' desk.
• Providing decent access to the innards for any ongoing modifications to the computers.
• Passing spouse acceptance factor ie Not too ugly.

So what is 4Ux2?

'U' is a rack mounting standard, where computers (normally servers) and other electronics or HiFi gear are a standard width, and varying multiples of the magic 'U' high. This desk allows for two 4U high computer cases to be mounted in it (or other 'U' equipment) - up to 4Ux2 in size.

Specifically for my purposes I designed for two 4U computer cases, as these don't require the small screaming fans of a 1U or 2U server chassis - an important factor when the front of the cases are only a couple of feet from your ears.

3U cases also exist, but are often a squeeze for normal sized video cards, and other options like water cooling.

1. 3/4" Sheets of Plywood (the good stuff - cross-banded Baltic Birch). Two 5' x 5' sheets were ample, with leftovers.
2. Piano Hinge. "1-1/2" x 72" Continuous Piano Hinge - Heavy Duty .060" Leaf Thickness - Antique Bronze - Matching #6 x 3/4" Screws", is what I used (from Amazon), hacksawed down to just under 60" long.
3. Keyboard Slides. I used a 14" 3/4 Extension, but these really come down to personal preferences, such as how far out you want the keyboard to be able to extend (the extension), do you want them to lock in place etc. I'd rather not recommend anything - especially if this will be for a standing desk (where pricy angled ones may be your thing). Keyboard slides are better than standard slides, as they normally have little support screws underneath, rather than the sides, however you may need to remove mounting hardware - mine expected to mount underneath a desk, rather than to the sides, so had a bracket screwing into the top that got in the way.
4. NavePoint 4U Vertical Rack Rail Pair DIY Kits. These come in pairs, so two pairs are needed, one for each side. I tried various other 'U' hardware, but these are ideal.

Tools

• Tape Measure - well D'Oh! I also used a fancy laser distance measurer, but it wasn't really necessary.
• Table Saw. All the cuts are 90deg, so a Miter saw is unnecessary, and a table saw is just easier (5' panels are pretty big to hand saw). I used a Fine Finish Crosscut Blade with 60 teeth for my 10" table saw - this project is fine work, not rough cutting firewood.
• A 2" Hole Saw - for cutting desktop cable holes, and ventilation. I also used a smaller 1 3/4" for some of the ventilation holes, but that isn't necessary.
• Power Drill - although I was mainly using self drilling screws, it really pays to give them some guidance (and prevent splitting) by drilling pilot holes first. Also needed for the Hole Saw.
• Battery Drill with a Torque adjustment for driving screws ('cause Power Drills will strip the heads or split the wood, and a screw driver is too painfully slow).
• Power Sander - did I mention that 5' panels are big? Sandpaper will take a long time. I used an Orbital Sander with 120 grit first, then 220 grit for a finer finish.
• Sand Paper (yeah okay I know what I said just above) - but this was 320 grit used just for the final finishing of the Desk Top surface.

Consumerables

1. Wood Glue - most of the desk will never be taken apart, so permanent joins are fine. Screws were used mainly to hold while the glue was setting, with most of the finished strength from the glue, so its important to use a good quality glue.
2. 1-1/4" Star Drive Washer Head cabinet screws. These were used to join two widths of 3/4" plywood. As this is closer to 1-1/4" thick than 1-1/2" you need to be very careful not to bury them or overtighten them.
3. 2" Deckmate Star Drive Coated Screws - these counter sink, so wood putty will hide. Use them for longer joins. Note: counter sunk screws are perfectly shaped for splitting wood, so they must have pilot holes drilled a little way to accommodate the heads.
4. Stain. I used Watco Danish Oil in Black Walnut for a very dark steam punkish look. Clear or lighter tones would depend on your decor.
5. Sealing - Mimwax Helmsman Spar Urethane Clear Semi-gloss.
6. Teflon tape - not essential, but taped to the desk under the computers makes sliding the computers in and out easier so less likely to scratch.

Expensive and optional Stuff

1. 4U Computer Case(s). I used SilverStone RM400 as they are lockable, not too deep (and are nice quality). However 'U' mounting is standard so most 4U 19" rack mount server cases will fit - depth permitting. With the 18.5" deep Silverstones installed, the case area has 4" behind for cable marshalling.
2. Standing Desk Base. This is optional. I eventually used the iMovR Vigor which is a premium product capable of lifting vast weights. Prior to that I had the desk sitting on two 2 drawer filing cabinets, which gave a good sitting height.
3. Through Desk Power Strips that take the place of a Desk Grommet. The ones you see in some of the photos are VILONG "2-in-1 combined power outlets". These have USB power at a convenient location, and allow for an out-of-three-year-old-reach power switch to turn off monitors and peripherals.
4. The other power strip you can see inset to the top of the desk is a "Furniture Power and Data Center - 2 Power, 2 CAT5e RJ45 and 2 USB Pass Through hub" This allows a convenient spot to connect network, charging and mains power, hiding the actual electronics from view.
5. "Qline Underdesk Pencil Drawer Organizer Tray 23" Slide Out". Yes, I finally had enough headroom in my keyboard drawer area (yay!) to even be able to add this nice storage knickknack to the top.

Note: All items were bought at retail, there is no sponsorship influencing my opinion.

The normal size for a desk is around 5 feet (60"). For this layout, that is the absolute minimum.

The reason, is that the 19" racks on each side of the desk are fixed constraints, and taking them out of the 60" leaves the center keyboard space about 22" wide. This fits a tenkeyless keyboard and mouse, but if you want a wider keyboard or more mouse waving-around room, you will need to adjust up accordingly (and find a supplier of larger plywood!).

Similarly, the depth of the desk at 30" suits the Silverstone Computer cases I used fine, and left ample space for cabling and exhaust space behind, but there are much deeper cases than the Silverstone.

The first construction step is to table saw to size the two 5' x 5' plywood sheets. While this can be done by one person, its safer and certainly easier if you have two. I did it with one, but used a table saw sled to manage cutting the large panels at 90degrees and without any lines being too bendy. The cutting guide (above) shows a way of laying them out.

The 4 pieces that run the full 60" width of the Desk are the easiest to tackle first ( these are also the main ones that need to be longer if you decide to supersize).

• The Base at 60" x 30" is the largest single piece of plywood. It is almost entirely hidden from view, so is a good candidate for using plywood with any blemishes you want to hide.
• The Hinged Top of the desk at 60" x 23.5" is the most important piece. It's not the largest single piece of plywood, but it is by far the most visible, so you should inspect all the plywood sheets and choose the best side of the best piece for the top of the desk. Cut it together with the next one :
• The Lower Back is just under 6.5" (6 3/8ths). Cut as a pair with the Hinged Top from a piece the same size as the base at 60" x 30" then cut the best part out along the length at 23.5" from one side, to form the Desk Top - so the Lower Back piece is the remnant, and ends up slightly under 6.5" - by the width of the saw blade. This gap is eventually covered by the piano hinge so (within reason) the blade width is unimportant.
• The Final long piece is the Upper Back at 60" x 5.5". It needs to be cut narrower than the Lower Back, by half the width of the piano hinge. So around an inch narrower with the hinge I used.

The Lower and Upper Backs need to be glued together, to form a single strong piece. This strengthens the back of the computer desk (prior to us drilling a few holes in it), and allows for clamp type Computer Monitor mounts, which put a fair amount of force on the back.

Its easier to sand the pieces prior to joining them, so I sanded all sides.

Glue and camp, making sure the back and sides line up. Once satisfied, a 1-1/4" Star Drive Washer Head cabinet screw every foot or so squeezes the glue in to hold. These should be drilled and screwed from the bottom piece to top, so the screw heads are hidden.

Once the glue is dry, is a good time to drill 2" holes for the Desk Grommets. A hole saw makes light work of this - drilling from one side until the center drill pokes through, then finishing the hole from the other side to prevent tear out. I was pretty free with the holes - 3 each side, so about 8 inches apart. Keep the very center of the desk free, as that is the monitor (clamp) location. You could use smaller holes, 2" is sized for standard Desk Grommets

In the accompanying photo the Backs are already glued, and their weight is enough to hold the rest of the unglued sections loosely together while fitting them.

As you can see in the first photo, the remaining items are almost all vertical, and all of these are exactly the same height, so easiest to cut in one job lot on the table saw. The width to cut is important, as this is the height of the 4U computer cases when assembled. A 'U' is 1 3⁄4 inches, so 4U is 7" exactly. Do NOT go under, err on the side of over, if you must - say 7-1/16th".

1. Front-to-back Uprights. These 4 pieces are all 28" long. The outside face of the Left and Right Uprights should be the better pieces, as these are much more visible than the two Internal Uprights. These pieces are all recessed from the front of the desk (Top and Base) in order to prevent the computer case handles from sticking out too far (see finished photo above), so an exact length isn't mandatory - just make all 4 identical, to your tastes. The rear section of the Internal Uprights needs a couple of hole saw drilled holes drilled to allow for cables. Don't do this until you have assembled all the uprights on the Base, so that you can choose where / how many holes you want.
2. Left and Right Dividers - these are completely hidden. They must be 17-3/4" wide to match the width of the 19" computer cases (minus 2 x plywood thicknesses). They need to be hole sawed up the wazoo to allow for ventilation. Rack mount computer cases blow all their exhaust air backwards - none out the side - so these holes are the only ventilation the computers have.
3. Rear Standing Plates - these four are just a bit of added strengthening, so size doesn't really matter - It's a compromise between airflow, access for cabling and monitor clamp mounts, and visibility/strength. I made them all fairly small at 3" as my desk faces a wall so cables won't be seen. I often move monitors around trying different orientations - so wanted lots of places I could clamp their stands to.

Once all are cut, sand everything and wipe off, so the assembly is less messy. I used 120 followed by 240 grit in an orbital sander. I also used the 120 grit to round off the human facing edges slightly.

For the top panel only (well depending on your masochism level - others too) follow up with 320 grit hand sanding to get the best finish.

Having cut and sanded all the parts (and glued the Backs together), this is the main jigsaw puzzle step.

It is very helpful at this stage to have at least one (preferably empty) computer case, to help get the fit exact, as you can see above.

Mount the Base on something horizontal and at a good work height - I used a couple of plastic saw horses. You should be able to stand up each of the vertical pieces on the Base if the surface is level, although placing the completed Back section on top to weigh them down certainly helps.

The four Front-to-Back Uprights, are the main items to locate. They each back onto one of the four Rear Standing Plates. These Standing Plates are in turn flush with the back of the Base. The side ones are also flush with the sides of the base, while the internal/center ones are centered on the internal Front-to-Back Uprights.

Each of the Front-to-Back uprights requires a Vertical Rack Rail to be screwed to the front. Mark which of the equipment securing screw holes you will use, and drill out some depth into the plywood behind them prior to permanently affixing the Rails.

The Left and Right Dividers (the pieces with all the holes in them) mount towards the back of each computer case area, flush with the front of the Back section above them. Once you have located these you will be able to determine how many, and where to drill cable holes through the rear sections of the Inside Front-to-Back Uprights.

To make the gluing easier (1) clamp a square block of wood to the base next to the upright to be glued, (2) then once you have applied the glue to the underneath of the upright, also clamp (at 90deg) the upright to the block. This keeps things stable while drilling and screwing from underneath/outside/top to secure the uprights. Note: if planning to mount the desk on something scratchable (or flat) countersinking the underneath screws is the way to go (my 2 drawer filing cabinets used for temporary staging had some good scratches on the top after their tenure as desk legs).

Glue Order:

1. Left and Right Front-to-Back Uprights. These are flush to the left and right of the Base, and back on to their Standing Plates at the rear corners, so you can be 100% sure they are in the correct place. Screw from underneath the Base up into the Uprights.
2. The Left and Right Standing Plates are next. They should already be in place so you knew where to glue their corresponding Front-to-back Uprights. As well as screwing from the Base, you can screw these into the Front-to-Back Uprights.
3. To exactly locate the Inside Front-to-back Uprights, make sure you have mounted all of the Vertical Rack Rails as this affects the width (the computer cases will be flush to the Rails not flush to the Front-to-Back Uprights). Make sure you have hole sawed a couple of cable holes in the back of these plates before affixing them, and please, please please use one of your computer cases to check the fit, prior to clamping and gluing!
4. The remaining Rear Standing Plates are next. These back on to the Inside Front-to-Back Uprights, and should be centered on them.
5. The Left and Right Dividers are the final step. The should each fit behind a case location neatly between a pair of Front-to-Back Uprights. They can be screwed into from all sides, as they should be snug to the front surfaces of the Back section. Above them on the Lower Back is where the piano hinge will eventually go, but hopefully you haven't installed it yet, as you won't be able to screw down from the Back section into the Dividers to secure the Dividers if so. These screws need to be counter sunk so the piano hinge which eventually sits on top of the screws will be flush.

Once everything is glued, its time to stain and seal. Temporarily remove the Vertical Rack Rails, as you don't want these stained. Follow the instructions on the tins (no point repeating them here), paying more attention to the finish of the outside/visible areas.

I used clean rags to apply the Danish Oil, and three coats of Spar Urethane.

The Desk Top should be the only section you have left unattached.

What about the keyboard tray you ask? Hopefully you hadn't yet cut it, as it now needs to be cut to fit, and odds are a pre-cut one won't. It fills as much space as you have left-to-right between the case areas, and can go back as far or as little as you like. The exact dimensions depend on your mounting hardware, and are best only measured now that everything else (bar the top/lid) is in place on an "as built" basis.

My keyboard tray ended up being 20-5/8th" wide, and 15-3/4" deep. Shallower might be better if you have a lot of equipment to fit behind it.

The Desk Top may have accessories - these are best (well easiest anyway) mounted prior to using the Piano Hinge to secure the Top of the Desk to the remainder.

Step back, have a cold drink, and admire !