Bay2Rack — old PC case → 6" homelab rack
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Towers used to come with 5.25" bays for CD drives. New cases don't, but ATX hasn't changed: that old case still
takes a modern motherboard. Bay2Rack is a parametric OpenSCAD adapter that screws into those bays and turns them
into a 6" mini rack, so an old tower becomes the heart of a cheap homelab: a router with VLANs, switches,
KVM over IP, Raspberry Pi blades and a patch panel, right in the front of the case.
Open the web generator (mirror if that
address does not load): say what you want in the bays (a fan or buttons, sockets, or a rack for devices), choose
what goes in every rack unit and every patch panel port, see it mounted in a real PC case (or a 90s sleeper), and
download a kit (.zip) with every STL, the bill of materials and the print settings. It all runs in your browser.
Just want to print? Pre-built variants are in stl/, with the screws and inserts they need.
Print the test pieces first and tune the print fits.
Building one? The build guide covers what to buy, the print order, the inserts, the
assembly and the cables and power.
Work in progress. Found a defect, a part that doesn't fit your case or a print problem? Open an issue
with photos and your case model. Measurements of other cases and rack gear, new modules and fixes are welcome as
pull requests. Cases reported so far: compatibility list · changes: CHANGELOG.
Evolution of the original
6" mini rack switch + patch panel in a 5.25" bay.
What you can build
| |
|---|
| Router with VLANs: the PC runs OPNsense / pfSense with a 4-port network card; a managed UniFi switch carries the VLANs, a second switch the servers, JetKVM + NanoKVM, patch panel | Network rack: 5 bays, two switches, a UniFi Express and a full patch panel |
| Raspberry Pi cluster: a UniFi switch and four Raspberry Pi 5 standing as 2U blades | KVM over IP: two trays, two JetKVM and two NanoKVM, HDMI and USB keystones |
| Audio: a Raspberry Pi 4 streamer, three 40 mm fans, RCA, 3.5 mm jack and Toslink keystones | Proxmox / TrueNAS box: no rack, just a front panel with an 80 mm fan and a power / reset button panel |
| UniFi: Flex Mini switch and UniFi Express | CD-drive front: an exact 5.25" bezel, flush with the case front |
A homelab from old PCs
The router keeps its rack in the bays: the switches, the KVMs over IP and the patch panel. The network cables of the
other machines (a Proxmox node, a TrueNAS box and an access point) come in through printed brackets in two PCI
slots at the back and end in the keystones behind the patch panel; short patch cords on the front connect them to
the switches. Cable colours are VLANs: clients, servers, the trunk to the access point and the WAN from the
router's network card to the fibre box.
The height problem
A 5.25" bay is 41.53 mm tall and stacked bays repeat every ~43.18 mm. A rack unit is 44.45 mm.
So N bays never hold N U inside the stack. The deficit grows by 1.27 mm per bay:
| Bays | Stack height | Flush (inside the stack) | Spare zone | Overhang (N U) | Panels stick out |
|---|
| 1 | 41.1 mm | 0U | 41.1 mm | 1U | +3.3 mm |
| 2 | 84.3 mm | 1U | 39.9 mm | 2U | +4.6 mm |
| 3 | 127.5 mm | 2U | 38.6 mm | 3U | +5.9 mm |
| 4 | 170.7 mm | 3U | 37.3 mm | 4U | +7.1 mm |
| 5 | 213.9 mm | 4U | 36.1 mm | 5U | +8.4 mm |
| 6 | 257.0 mm | 5U | 34.8 mm | 6U | +9.7 mm |
The design handles this with one parametric model instead of one model per bay count.
Variants
Two independent choices give four families. The pre-built files cover 1–3 bays (1–4 for plate-flush); the model goes up to 6:
| Flush: N−1 U + spare zone, nothing sticks out | Overhang: N bays = N U |
|---|
| Plate front: flat frame behind the rack panels | plate-flush: the spare zone takes a swappable filler (6-port patch, vent, blank) | plate-overhang: the frame is a few mm taller than the stack |
| Bezel front: the exact outline of stacked 5.25" drive bezels | bezel-flush: flush with the case front like an original drive, patch panel cut into the bezel | bezel-overhang: the bezel stays flush, only the rack panels overlap the case front |
Use the plate front when your case front is flat at the drive bays. If the case has a plastic front that
stands out from the metal, use the bezel front and set bezel_depth to how far that front stands out.
Other knobs: units_override, overhang_align (center/top/bottom), spare_pos (top/bottom/split),
and the spare-zone fill (keystone, buttons, vent, cable, label, fan40, fan80, blank).
The fill can be separate (a screw-on panel in the same plane as the rack accessories) or integral (cut into the frame).
This is the beginning of the README. Read the rest at the original. Read the full README ↗
