rack-build — 3D-printed 19" rack panels

Three parametric OpenSCAD panels for a home 19" rack. Source files are in scad/; the printable STLs are attached to each release rather than kept in the repo. Printers: 2x Prusa i3 MK3S (250x210 mm bed).

Test-first, every panel: print the piece with a snap-fit or clip mechanism first (right half of the 1U, column 1 of the 2U, one keystone piece) and dry-fit the hardware before committing to a full print run. Several mechanisms here are first-pass designs validated by geometry checks, not by an actual print — see the cautions under each section.

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Print settings (all three files)

• Material: PETG
• Orientation: every panel piece prints with its front plate face-down on the bed (the .scad files handle this rotation automatically — just slice the STL as exported, don't reorient it in the slicer)
• Supports: none, for any piece. Stops, bosses and rail ends rise at 45 degrees from the wall they grow out of, and the only overhangs left in the exported STLs are short bridges (12mm inside the Hue push-rod pier, 16mm under the Pi sled, a 48mm strip of floor over the PoE window) and the tops of horizontal screw holes and pegs. A slicer's automatic supports will still build towers under every one of those holes, so leave supports switched off. This comes from measuring the STLs, not from a finished print.
• Layer height / infill: no hard requirement from the design; 0.2mm / 15-20% infill is a reasonable default. Parts with threads cut directly into the plastic (standoffs, bosses) will hold a self-tapping screw better with higher infill in that specific region if your slicer supports it.

Installation

To print the panels as published, download the STLs from the latest release; nothing needs installing. To change the designs or export the STLs yourself, you need OpenSCAD and this repository.

On macOS, install the OpenSCAD development snapshot with Homebrew (the release workflow builds with the openscad/openscad:dev image, so the snapshot is the version to match):

brew install --cask openscad@snapshot

The cask doesn't put openscad on your PATH, which build.sh expects. Link it:

ln -s /Applications/OpenSCAD.app/Contents/MacOS/OpenSCAD /usr/local/bin/openscad

(use /opt/homebrew/bin instead of /usr/local/bin on Apple Silicon).

Then clone the repository:

git clone https://github.com/davidwkeith/rack-build.git
cd rack-build

Building

STLs are only generated by release builds: pushing a v* tag runs the release workflow, which exports every piece and attaches the STLs to a GitHub release. To export them yourself into stl/ (ignored by git; needs openscad on your PATH, see Installation):

./build.sh release

The preview images in this README are committed. After changing a source file, re-render them with:

./build.sh

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Hardware shopping list (consolidated)

Qty	Item	Used for
18x	M3 x 8mm socket-head cap screw	Panel joints: 3 (1U Hue/Pi) + 12 (2U audio) + 3 (keystone)
18x	M3 hex nut	Panel joints (nut traps)
12x	1.75mm filament offcuts, ~10mm long	Joint alignment dowels: 2 + 8 + 2
8x	M2.5 self-tapping screw	Raspberry Pi 5 to sled standoffs (4 per sled); not needed where a HAT's own standoffs do the job
2x	M3 self-tapping screw	PoE++ bracket standoffs
4x	M3 x 6mm pan-head self-tapping screw	Kinter MA170 tab mounting (2 per amp; 6x with a third zone). The tabs are 2mm, so the longest safe screw is 7mm; 6mm is the standard size that fits
12x	M6 cage nut + screw	Rack ears, 4 per panel (the 2U has 8 holes; 4 is enough)

Every joint is two 6mm flanges with a 3mm head recess on one side and a 2.8mm nut trap on the other, so an 8mm bolt ends inside the nut. A 10mm bolt works too; it stands 1mm proud of the flange, clear of every device.

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1. 1U — Hue Bridge + PoE++ injector + 2x Raspberry Pi 5

Assembled, with the separately printed sleds, push-rod and pin in red.

Source: scad/rack-1u-hue-pi.scad Pieces: rack-1u-left.stl, rack-1u-right.stl, rack-1u-sled.stl (print this one twice — one per Pi), rack-1u-pin.stl, rack-1u-rod.stl

• Left piece: Philips Hue Bridge (model 3241312018) — front push-rod reaches the top sync button, two split snap-fit posts engage the Bridge's own keyhole + oval mounting slots. The UniFi PoE++ Adapter (60W) clips onto 2 printed standoffs on the floor's underside (92.80mm hole spacing, front-to-back) and hangs below the shelf; a 48x28mm front window keeps both port labels readable.
• Right piece: two Raspberry Pi 5 + PoE HAT sleds — one Home Assistant, one TBD. Each slides in from the front and latches via a flexing tongue riding a ratchet tooth, rather than lifting out from above (earthquake country — a Pi swap never needs the panel pulled from the rack). USB ports face front. The bays are sized for a Pi 5 under a 52Pi P30 PoE+ HAT, a ~30mm stack; that is tall enough that the bays are open at the top of the front plate rather than framed.

Joint: 3x M3 bolt + nut, 2x filament dowel, per half-to-half seam (one seam total on this panel) = 3 bolts, 3 nuts, 2 dowels.

Assembly:

1. Dry-fit one Pi sled into the right piece before printing a second — check the latch clicks in and lifting the pull lip releases it cleanly.
2. Bolt the two halves together while both are still empty: the bolt heads sit in the Hue bay and the nuts in the first Pi bay, and the Hue covers two of the three heads once it's in. Heads go in from the left piece's face, nuts tighten on the right piece's face. Seat the filament dowels first so the faces can't shift while you torque the bolts.
3. Push the Hue Bridge down into its left-piece pocket until the snap posts click; thread the push-rod and pin into the button-pusher channel from the front.
4. Screw the PoE++ adapter onto its 2 underside standoffs (M3 self-tap). Check there's genuinely empty space in the rack slot directly below — the adapter hangs ~31mm below the shelf floor.
5. Screw each Pi 5 onto its sled (4x M2.5 each, 8x total), USB/Ethernet toward the pull lip. If the HAT's standoffs have threaded studs, run those through the board into the sled's standoffs in place of the screws. Then slide both sleds into the right piece from the front until they latch. To pull one, lift the lip under the Pi's ports and draw the sled out by it.
6. Mount in the rack with M6 cage nuts.

Open items (all need the real hardware, not more modelling):

• Needs calipers: the Hue snap-post offsets are a photo estimate — if a post doesn't land in its slot, that's the first thing to re-check (khole_dy / oval_dy).
• Needs a test fit: the Pi + HAT height is 52Pi's published ~30mm, not a measurement. The model leaves it 2.7mm under the top of the 1U; set pi_stack_h if yours differs.
• Needs a test print: the Pi sled latch (flexing tongue + ratchet tooth) clears every interference check in the model but is untested as a physical mechanism. ramp_h in the .scad file is the knob to back off if the tooth grips too hard to release by hand.

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2. 2U — Audio stacks (up to 3 AirPlay zones)

Source: scad/rack-2u-audio-stacks.scad Pieces: audio-1.stl, audio-2.stl, audio-3.stl (or audio-2-stack.stl in place of audio-2.stl for a third zone)

Three bolt-together columns. Each stack pairs one AirPort Express (upper U) directly above one Kinter MA170 amp (lower U), one stack per AirPlay zone.

• Columns 1 & 3 (zones 1 and 2): AirPort front-flush (face against the plate, behind a full-face window for the status light) and two curved holders hugging its rear corners so it can't slide back; Kinter behind a 100 x 40mm window its knobs poke through (they stand 20mm proud of the front plate, for finger adjustment), with two printed screw bosses under the amp's factory mounting tabs. Front-to-back vent slots under the amp and in the upper floor behind the AirPort let its heat rise out of the stack. The amp floor sits 4mm up so those bosses stay inside the panel, and the AirPort floor sits 1mm above the amp rather than on the U line.
• Column 2: blank — the same floors and joints with no windows, holders or bosses. For a third zone, print audio-2-stack.stl as the middle piece instead: it is the same stack as columns 1 and 3 and bolts up identically.

Joint: 2 seams (col 1-2, col 2-3), each 6x M3 bolt + nut (3 Y-positions x 2 Z-levels, one level per U) + 4x filament dowel = 12 bolts, 12 nuts, 8 dowels total across both seams.

Assembly:

1. Print column 1 first and dry-fit an amp and an AirPort in it before printing the rest.
2. Bolt the empty columns together in order (1-2, then 2-3), dowels first, same as the 1U panel. The bolt heads and nuts sit inside the bays, so this has to happen before the amps go in.
3. Slide each Kinter MA170 into its lower U from the rear until its face meets the front plate, and screw it to the floor bosses through the amp's factory tabs. The two driver holes in the upper floor sit straight above the tab screws: lower each screw through on the driver.
4. Slide each AirPort Express into its upper U from the rear until its face meets the front plate and the two curved rear holders cup its back corners. The driver holes stay clear either side of it, so an amp can come out without disturbing the AirPort.
5. Mount with M6 cage nuts — these columns carry protruding ear tabs that reach the rack's true 482.6mm width (the 3 columns' own content only spans 408mm).

Open items:

• Tab screws: the amp's tabs are 2mm, so the blind pilots (1mm skin under them) take a screw up to 7mm; M3 x 6mm gives about 4mm of grip.
• Needs a test fit: the amp bay is built from caliper measurements of one MA170 (103 x 70 x 43mm case, 124.5mm across the tabs, slots 113mm apart and 30-42mm behind the face) but hasn't been printed. Fit an amp to column 1 before printing the rest.

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3. 1U — 24-port keystone patch panel

Source: scad/rack-1u-keystone-panel.scad Pieces: keystone-left.stl, keystone-right.stl (12 ports each)

Standard 14.5 x 16mm keystone cutouts, industry-standard across brands. Panel's thinned to 2.5mm specifically so keystone clips can actually engage (the rest of this rack's panels are 4mm — too thick for most keystone jacks' spring clips to reach). Ports sit low in the panel, leaving ~20mm of clear space above each one for a label.

Joint: 3x M3 bolt + nut, 2x filament dowel = 3 bolts, 3 nuts, 2 dowels.

Assembly:

1. Print one piece and test a single keystone jack before printing both — clip tolerance varies enough by brand/model that this is worth confirming. If jacks won't seat, thin the panel further; if they're loose, that's likely fine (the clip still does the retaining).
2. Bolt the two pieces together same as the other panels (heads from the left piece, nuts on the right, dowels first).
3. Snap jacks in from the rear, terminated or not — they self-retain, no bracket needed behind the panel.
4. Mount with M6 cage nuts.

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Also in the rack

Two things in the rack aren't these panels:

• Router: the UCG Fiber and its power supply sit in the UCG Fiber + PSU 19 inch modular rack mount by Maurício Pessoa on Printables, printed as published.
• Switch: a Ubiquiti EdgeSwitch 24 (ES-24-250W), a 1U unit that mounts on its own rack ears with no printed parts.

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Superseded / not included

• rack-1u-kinter-amps.scad — standalone single-amp panel, replaced by the 2U audio stacks (each amp now pairs with its own AirPort Express instead).
• An earlier "keyhole" cable-management panel design was replaced entirely by the keystone panel above — no files from that version exist.

Both are left out of this collection since they're not part of the current build.

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Credits

All geometry here is original, but two ideas came from other people's models on Printables:

• The Hue button pusher follows RobinUit's "button pusher" (model 480200).
• The front-loading Pi sleds nod to JaredC01's "1U Rackmount Cluster" (model 285853).

The Hue snap-post spacing was cross-checked against vladimir.aubrecht's remix (model 125408) of Luther2k's Hue rack mount.

License

ISC © David W. Keith