Digitus 10" SOHO Rack Fan Duct — 120 mm, No Drill

A Synology DS224+ and a mini PC in a closed 10" wall cabinet were running too hot in summer. Commercial rack ventilation kits are expensive and nearly all of them require drilling the cabinet.

What it fits

Made for the DIGITUS SOHO 10" network wall cabinet, 6U (330 x 312 x 300 mm, 240 mm usable depth, glass door). The 9U and 12U versions of the same series very likely share the same bottom pass-through, but I have only tested the 6U.

The opening it fits is 143.5 x 68 mm. Measure yours first. If it doesn't match, the .scad file is parametric: change "hueco_x" (opening width) and "hueco_y" (opening depth) in the first lines, press F6 in OpenSCAD and export. Two numbers, no coding needed. Fan size and forward offset are parameters too, in case you have less clearance to the wall behind.

The clips use a 4-tooth ratchet at 0.8 mm pitch, so they grip any sheet metal between 1.0 and 3.4 mm. No need to measure the thickness.

Parts

Body — 171.5 x 129.7 x 74 mm — approx. 261 g

Clamp bars, x2 — 90 x 16 x 12 mm — approx. 39 g

Mesh frame, optional — 154 x 134 x 39 mm — approx. 92 g

The frame is only needed if you want a removable filter. Otherwise put the mesh straight under the fan, held by the same screws with wide washers.

You also need

A 120 x 25 mm fan. I use a Noctua NF-A12x25 5V powered over USB. Any 120 mm fan works, but pick one with decent static pressure and avoid models optimised for open cases.

4 x M4x35 self-tapping screws, for the fan.

4 x M4x16 countersunk DIN 7991 screws plus 4 M4 nuts, for the clamping.

PVC mesh or insect screen, cut to 128 x 128 mm.

2 mm adhesive EPDM tape for the gasket.

Printing

PETG. A closed rack easily goes past 45 °C and PLA will deform, so this one is not optional. Use 0.2 mm layers, 4 walls and 20 % infill.

No supports. The body rests on the flat fan face and every surface is above 45°. For the clamp bars, the face with the small holes goes down on the plate; they come pre-oriented in the file.

Your slicer will warn about a floating overhang. Ignore it. I checked the mesh layer by layer at 0.2 mm looking for regions with no contact to the layer below, and there are zero islands anywhere in the part. What the checker flags are flat 2-3 mm ledges that are fully supported around their whole perimeter.

Assembly

1. Push an M4 nut into each bar, through the large hole until it seats in the internal hex. Add a drop of superglue so it can't fall out.

2. Stick the EPDM gasket around the flange.

3. Push the body into the opening until the four clips click.

4. From inside the rack, drop each bar onto its two guide posts. They self align and cannot rotate.

5. From below, insert the four M4x16 and tighten crosswise, gradually. Stop as soon as the gasket compresses.

6. Mount the fan last, blowing upwards. Check the arrow on the fan frame. The mesh goes between the fan and the screw heads.

The fan really does go on last: once it is mounted you can no longer reach the clamping screws.

Notes

The body is asymmetric. The cone leans forward to clear the wall behind, so mounted backwards it will not fit.

The two rear screws need the driver tilted about 15°. The front two go in straight.

Tested on the 6U SOHO cabinet only. If yours differs, use the .scad.