Storage/Computer Rack

When working from a small space, its always a challenge to make best use of every inch of it. During lockdown in the middle of 2020, I decided to gut my whole workshop and store everything in my second shop. I took lots of measurements and started to sketch out ideas to best make use of the space.

The first issue was with space for storage of small parts, evaluation boards, and how to keep the parts for various projects together.

The second issue was with recall – when I stow away a part, project or tool, how to locate it again.

Plastics

A friend from my local hackerspace gave me a huge pile of Euro stacking containers, similar to these:

https://www.plastor.co.uk/euro-stacking-containers-with-and-without-lids-folding-containers/coloured-euro-stacking-containers/

These were the standard 600x400mm footprint kind, in various heights.

I had three sizes, mostly the small kind which were about 73mm high. A fair few of the bigger 150mm high type and a handful of the 120mm high kind.

I came up with a simple arrangement (using inkscape!) which would fit as many as possible in my available space.

Computer stuff

I’ve had a few 19″ racks over the years, and recently got rid of the last one, as it was just not very space efficient. I like mounting kit this way, as its very tidy and sturdy. I decided that this storage rack could encompass a 19″ section too, and that would take care of a lot of my storage issues.

On eBay, rack rail kits are available for very little outlay, so I ordered a couple that were about the right length, and designed around them:

This part is available from Amazon

Available Space

I started out measuring the rear wall of the internal space, and sketched it in FreeCAD. I was going to design the whole thing in CAD and then break the assembly apart to get the sheet sizes and drill locations. Then I got impatient and just sketched it manually instead. This sketch was my reference to make sure it would actually fit when assembled.

I made a mental note to ensure that I check there was enough floor space to assemble it, that the sheets would fit through the door and that if I assembled it face-down, I could actually erect it without fouling on any of the timbers inside the space.

Workshop rear wall limits. Top details show roof support timbers, rectangular cutout shows size and location of a double power outlet on this wall

The Design

The design is a very simple box. It has internally divided into five columns, the leftmost is setup so that the internal size, taking into account the rail kit, gives the correct 19″ horizontal hole-to-hole space needed for rack mounted kit.

The remaining space is divided into four equal width columns, with internal space of 410mm. The boxes are fitted so they protrude 600mm away from the rear wall, and 400mm wide.

The extra 10mm gives 5mm clearance per side.

To keep costs to a minimum I decided to use the cheapest, sturdiest material that was up to the job – 18mm MDF sheet. Butt-jointing, wood glue and 7x50mm confirmat screws to care of the construction. EBay supplied these, together with the matching drill. This also handily drills out the wider section for the shoulder of the bolt to drop into, as well as countersinking at the same time. Easy!

7mm x 50mm confirmat screws
7mm x 50mm confirmat drill bit

These were provided by eBay seller peter-diy. Go check out his store.

The rails were held on with some M4 x 30mm button head allen bolts:

M4 x 30mm button head allen bolts

These were provided by eBay seller boltbase. Go check out his store.

First Pass Layout

Initial layout, rack 400mm depth

After making more detailed calculations, I determined that I needed to spin the trays 90 degrees, and have the trays aligned so they are narrow-side on, making each column 400mm + clearance, in width.

Once the 19″ rack section was added, and taking into account the 18mm uprights, plus clearances, the total length of the top/bottom sheets exceeded 2400mm.

Since that’s the standard sheet size available, and about the limit I can fit in my car, I needed to compress it horizontally to fit. Annoyingly, I needed to sacrifice floor space in front of the rack. It was only 200mm, but every little helps in small space.

The second issue was vertical clearance. After allowing for some vertical tray float, for assembly, any wood expansion (unlikely for MDF, mind) and inaccuracies in drilling and wood thickness, it was looking just a little too tight. The only option was to loose a row of the small trays from the top. So it became a 4×8 array, not 4×9. Which sucked a little, but it was still massive 🙂

Support batons

I had some good quality pine left over from building a second workshop, so I cut those up into batons for supporting the drawer units at each side. This needed lots of drilling, gluing and screwing, but that cost nothing but time, as I had everything to hand.

The final tray count was 4 columns x 15 rows or 60 trays. Trays were supported by two batons. That made 120. It took quite a while.

I made the batons 18mm high, 20mm wide and about 580mm long (limited by the wood I had to hand) The trays have little shoulders on the bottom, which needed to line up with the batons, but that was just a matter of making the spacing correct to not foul.

Each baton had four holes drilled and countersunk. The idea was to never screw into the MDF (shown in black below), only the solid pine baton (shown clear below).

Some short screws (Blue) were located to give a decent amount of purchase on the 20mm wide baton, once 18mm of MDF was penetrated. This served for the batons at either end of each row.

(Left) Inner support baton details. (Right) Outer support baton details

Longer screws were needed for batons screwed through the three inner supports, this time the screw needed to pass through one 20mm baton, 18mm of MDF and still have a decent amount of purchase on the opposite baton.

Pre-drilling

It was very important to pre-drill the holes in the sheets, and also the batons to match. I made a simple sliding jig from spare sheet and some metal offcuts.

The jig was arranged to have four holes near one end, and to slide parallel over a sheet.

To prevent sideways slip and rotation a few metal plates were added at the edges.

With the first sheet marked up with the correct baton centres (i.e. where I wanted to drill the holes) I could simply slide the jig to the next baton location, drill four holes and repeat.

Once the first sheet was fully drilled and checked, it was a simple matter to clamp the other sheets to the first, using it as a massive drill jig.

This made is possible to replicate the hole pattern accurately enough.

Once all the sheets were drilled, the drill jig was modified to hold batons in an appropriate way, so they could also be pre-drilled.

Due to the quantity involved and the need to countersink the baton holes as well, this took quite some time.

Final Layout

Final layout settled on, rack 600mm depth

The final layout shows how the sheets fit together. Green, are the longest at 2212 x 600mm, and form the top and bottom. The bottom sheet bears all the weight of the structure and contents, in compression, so this is fine.

Dark blue, are the vertical sheets which bear the distributed weight of the contents, again in compression. For ease of assembly, the inner sheets sat directly on the bottom, with the end sheets sitting on the floor.

These end sheets were secured to the top and bottom sheets with four confirmat screws at each end, into the end of the corresponding top/bottom sheet.

The inner sheets were secured top and bottom, again with four confirmat screws at each end.

Finally any tendency for the structure to move out-of-square was counteracted by a single 2400 x 1200mm sheet of OSB.

The sheet was divided into three long strips approx. 2212 x 400mm and screwed into the back of the rack, spanning all the uprights. The top and bottom OSB sheets were overlapped with the top and bottom sheets and screwed into them.

OSB support sheets showing numerous screw locations

Before drilling the OSB sheets, the structure was trued, by measuring the diagonals, and pushing the bottom sheet sideways to equalise.

Once trued, the OSB sheets were clamped and drilled into the end of the structure to prepare for gluing and screwing.

All wood joints were glued before final screwing.

Final Touches

After leaving overnight for the glue to dry, the batons were fitted, again much glue and lots of screws. When that had chance to dry off, paint was applied.

First a coat of watered-down junk emulsion to prime and seal the surface, followed by a couple of coats of boring old white.

Rough installation, pretty random labelling. This will be improved over time.

Accessorise

The reason for the 900mm rack height in the final layout, is to allow a workbench to butt up against the rack, with the surface of the bench lining up with the bottom of the rack. This allows me to add rack mounted electronics equipment, such as power supplies or anything else I decide to build. With the bench in place, the ugly UPS is below it, out of sight, doing its thing. Above the bench, everything is accessible to anything on the bench.

Currently there is a Cisco managed switch and my recent cheapo NAS build in place.

I added a shelf I had lying around to park external USB drives, and a rack mounted power distribution unit.

19″ rack mount PDU from eBay

This was supplied by eBay seller kaza-uk and was surprisingly good quality for the price.

One wouldn’t normally put such a thing in a rack, but since it will be very close to my bench, it was appropriate to supply power at this location.

I’m sure this project will develop further over time, but for now this is as much as I need to do – other builds in progress!