7. Case Central Structure

Up until now, you’ve been making cards for this project and those are relatively easy compared to making the case. The process of making the cards is also more forgiving, because if you mess one up beyond repair you waste far less material.

Step 1. Cut and Wash Cable Management Clips

One of the first groups of parts you’ll need for making the case is the wire management clips. The design for these is in the file Step 7 – Side Rails v11.svg.The indicated numbers of each to make are guesses, which are hopefully higher than what you’ll need. However, these tend to break, so you may want to cut spares.

Wire Management Clip - Apart Wire Management Clip - Together

Also, since these tend to break, don’t glue them in. If you do a good enough job making them fit tightly in their mounting slots, they won’t need to be glued anyway.

Step 2. Cut and Glue Side Rails

The side rails primarily consist of parts 7J, 7K, 7M, and 7N. These provide the central support structure that holds up all of the cards.

Before cutting the side rails, you should cut the card locking clips. Then, cut some test pieces to test various slot widths for the card locking clips and wire management clips. If you wait until you have the ideal slot widths figured out for these slots, you may only need to cut parts 7J, 7K, 7M, and 7N once. If you don’t experiment, you’ll probably need to cut these parts at least twice. Further information regarding this process is provided in notes within Step 7 – Side Rails v11.svg.

You will also need to measure the thickness of the edges of the cards you made previously. If you followed instructions and made them out of your thicker acrylic, they may be somewhat thicker than 9mm. Measure both sides of each of the four cards you made previously and choose the largest of the 8 values, then add 0.2 mm to get your rail spacing. In the design files provided for making the side rails, the rail spacing is 9.2 mm. If your largest measurement is larger than 9.0 mm, you’ll need to expand the rail spacing to compensate.

Resizing Detail

Once parts 7J, 7K, 7M, and 7N are cut, clean them well to prepare them for gluing. The first phase of gluing them will be to tack the finger-like structures of 7M to 7J and 7N to 7K. To get them aligned properly for tacking, place 7M on top of 7J and 7N on top of 7K and then populate all the wire management clips slots, as shown in the picture below.

Side Rails - Tacking

Once the support rails have the clips installed, apply a very small amount of cement to the tip of the rail. Try not to apply so much that it reaches the base of the clip.

Side Rails - Tacking 

But if the cement does happen to reach the base of the clip, just carefully remove the clip. But make sure you don’t ruin the alignment of the rails in the process.

Side Rails - Tacking

Tack all of the rails, even those that don’t have a wire management clip in. After the rails are tacked and the tacking cement has had a few minutes to soak into the plastic, glue the rest of each part. Then, set them aside to cure for a few hours.

Step 3. Cut and Test Fit the Base and Top Plates

Before cutting the base plate and top plate, measure the thickness of the associated tabs at the bottom and top of your side rails. The file is designed for these tabs to be 9 mm thick. You really want the slots (on the base especially) to be very close to the exact thickness of the matching tabs. The tighter the fit, the better the joints will be after they’re glued. These joints will probably take more abuse than any others in the build when you’re moving this thing around, so you want them to fit very tight. If the tabs don’t quite fit after the base and top are cut, they can be sanded or filed down a little. Just be sure not to overshoot and make them too loose.

Once the tabs fit, make sure you clean them up well before moving on. But don’t glue them in place yet. For now, it’s satisfactory to leave these parts unglued, but assembled on the table. You’ll need them together to test fit other parts with them soon.

Step 4. Cut and Glue the Central Plate

Cut and glue the central plate. If you have any difficulty lining the bottom layer up with the middle and top layers, glue the middle and top layers first and let the adhesive set, then fit all three layers together with the side rails and base plate. With them together, tack the bottom layer well in several places and give the tacking a couple hours to dry. Then, remove the central plate and finish gluing it. Set it aside again until the adhesive forms a firm bond.

Step 5. Cut and Glue the Hard Drive Power Board Cover

This one is fairly straightforward. Cut the parts for the hard drive power board cover, then glue the parts according to the etched lines provided. When it’s glued, it should mate well with the central plate. Test fit the parts before gluing if you’re unsure which way it goes.

Step 6. Cut and Glue the Top Compartment Partition

Glue 7D, 7E, and 7F together. Compare them to the picture before gluing them to make sure you don’t have them backward. After gluing, let them dry for an hour or so.

Step 7. Fit Main Support Structure Together

This step really involves cutting and installing many of the structural parts from the file Step 7 – Base and Top Plate.svg. This is quite a lot of parts and the process may be difficult. Unfortunately, I don’t have pictures of the process of assembling these parts. However, the following image should help quite a lot, as I’ve numbered all of the difficult parts.

Labeled Top Shot

  1. Place the side rails in the base, if they aren’t there already.
  2. Fit the central plate with the side rails. Make sure it’s fitted tightly.
  3. Fit the top compartment partition and part 7C with the rest of these parts.
  4. Fit the case top (7A) with the rest of these parts. Wiggling the tabbed parts relative to each other a little bit may be required.
  5. Spend a little time inspecting all the tabbed joints you just fitted together. Are they tight? If not, do whatever is necessary to tighten them. This may require sanding a few of the tabs to get it all to fit tightly. Clean them well after sanding them so as not to introduce dust into any of the joints.
  6. Once the parts all fit tightly, elevate the base of the case with a few blocks of wood.
  7. Check one last time to make sure the whole assembly is square and the clearance between the top and bottom plates is the same all around. I recommend measuring the clearance at all four corners. If the clearances at the four corners are not within a range of 0.2 mm, adjust as necessary to correct it.
  8. Glue all the tabbed joints associated with these parts, including those for fitting the side rails with the base plate.

You may also cut parts 7B, 7Q, 7G, 7H, 7T, and 7S. However, don’t glue them in yet.

Step 8. Cut and Install Middle Backplate

Cut the plates from the file Step 7 – Backplate v4.svg. If you’re sure you always want to use Raspberry Pis in this build, you can glue in the middle one for extra support. If you may want to upgrade it later, you may not want to glue it. But, if you don’t glue it in, I recommend moving the unit very carefully once the cards are installed, as it will be heavy and not as strong as it could be. If you choose not to glue it in, simply set all 3 plates aside for now.

Step 9. Install Fans on Upper Backplate

The upper backplate has space for two 80 mm fans. Try installing the backplate to figure out if you understand its correct orientation. The photo below shows it properly installed.

Case Central Structure - Assembled Left Side Detail

The rectangular opening on the right of the upper backplate is there for the cables that power the power cards. Oriented as it is in the photo, the thinnest part of the card around this rectangular opening is at the top. The intended mounting orientation for the fans is as shown in the photo, with the label side out. I believe this orientation will provide maximum air circulation within the case. Orient these parts as described and then screw the fans to the upper backplate. Once again, put the backplate aside in a safe place for later use.

Step 10. Install Wire Management Combs

Install the wire management combs, which you probably cut previously. It’s likely the combs will not fit very tightly; this is fine, since they’ll be backed with other parts. Glue them in and let the glue set for a couple hours before continuing to work with these parts.

Step 11. Install Wire Management Brace

Cut and install the wire management brace. This part is meant to be placed directly behind where the hard drive array will slide in. Do not let it overlap the track for the hard drive array. If you use a right angle piece to line it up, you can line up the edge of it with the back of the hard drive array track. The top of it should touch the top of the case.

Wire Management Detail

Step 12. Install Locking Clip Stops and Support Braces

Generally, when you cut the support braces, you’ll end up with some of them facing one way and the rest facing the other way. I recommend pairing them up and installing them in a consistent pattern.

Be mindful of the fact that a few of the braces will need to be placed where they’ll overlap with wire management clips, once those are installed, too. I recommend checking the wire management clips as you go and filing down a little of the support brace if its placement conflicts with a wire management clip.

Turn the case so it’s laying on its left side. Then, glue in the locking clip stops and give the adhesive about 15 minutes to soak in. Then, install the associated support braces. I recommend holding the support braces with pliers while gluing them in. The following picture shows good detail of how these should look once they’re installed.

Wire Management Detail

When I designed these support braces, I designed tabbed and untabbed versions. I laid out several of the untabbed version in the .svg file, but they don’t have a specific destination within the build. Simply use them anywhere you feel that you need a little extra support. I used about a half dozen or so of these by the time I was done and I’ll probably add a few more in the future.

Step 13. Cut and Install Card Locking Clips

Install the card locking clips. When installing them, be sure to only glue the tab. The rest of the clip is meant to act as a lever and will not function properly if it gets glued to the side rail support. The clips are designed such that glue won’t easily wick from the tab to the lever, to make it easier to glue them properly.

I recommend turning the case on its side to do the gluing. Glue the clips on one side, let it set for 30 minutes or so, then turn it over and glue the clips on the other side.

Step 14. Install Power Cable Harness

Glue in the power cable harness, in the location indicated in the picture below. The larger, thicker part of it will need to be glued to the bottom of the central plate. The thinner part should then be glued to the top of the thicker part after it has had some time to cure.

Routing Power Cables Detail

Future Development

The tabs that mate with the top plate stick out slightly. The intention is that these tabs should be sanded flush after the joints are filled with something clear. However, I never quite figured out a good procedure for doing that. If I get that part right at some point, I intend to add it here.

6. Ethernet Switch Cards 7. Case Central Structure 8. Case Side Panels

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