Case & Spacer

The PolyKybd case and spacer can be 3D printed (resin SLA recommended) or CNC machined.

STL files

Part	File
Left case	parts/export/case/case_polykybd_split72_left_r7.stl
Right case	parts/export/case/case_polykybd_split72_right_r7.stl
Spacer (×2)	parts/export/case/spacer.stl
Spacer for the LED diffuser frame (×2)	parts/export/case/spacer_diffuser_frame.stl

Tip

Always grab the latest revision from the repo — r7 is current at the time of writing. Superseded revisions are no longer kept in the tree; they remain in the git history if you ever need one.

All files are in the PolyKybd hardware repo.

The spacer keeps the right distance between the plate and the PCB and is printed twice (once per half):

Note

If you fit the LED diffuser frame, print spacer_diffuser_frame.stl instead — the plain spacer leaves nowhere for the frame’s web to sit. It is notched on both faces, so the same part works on either half, and spacer_diffuser_frame_4x.stl puts four on one plate.

Printing recommendations

Resin (SLA) printing gives the best results — the fine details of the case walls and display cutouts come out cleanly.

FDM printing is possible but the surface finish and dimensional accuracy are lower.

Tip

If your resin print has slight warping (common with large flat parts), use a hair dryer to gently warm the case, then press it flat under a heavy object for a few minutes. It reliably corrects minor deformations.

CNC machining

If you have the case CNC machined instead of printed, add threaded inserts to the four corner screw holes — the M3 screws need something to bite into since CNC aluminium won’t self-tap.

Metal case

There is a dedicated metal case design, re-authored for machining rather than exported from the printable one — so it ships as proper B-Rep STEP, which is what a machine shop actually wants to quote and program from:

Part	File
Left, STEP (B-Rep)	parts/export/case/metal-case-left.step
Right, STEP (B-Rep)	parts/export/case/metal-case-right.step
Mesh preview	parts/export/case/case_polykybd_split72_metal.stl, .3mf, and ..._metal-bottom.stl

Caution

The first machined set has just arrived and is being fit-tested against a real build — plate, PCB, spacer and screws — so treat these files as not-yet-confirmed and expect the dimensions to move if the test turns anything up. The printed r7 case above is the validated one.

The source is parts/case/case_polykybd_split72_metal.scad, with the STEP re-authoring pipeline in parts/case/step/. The threaded-insert note above still applies.

Screws and nuts

The current case revision (r7) uses:

• 8× M3×10 hex screws with rounded heads
• 8× M3 hex nuts (press-fit into the case corners)

Note

The nuts are required from revision r4 onward (including r7). Older revisions (before r4) did not require nuts — the screws threaded directly into the resin.

Felt case (alternative)

A simpler felt case design is also available for a softer, quieter desk feel. See felt_case.jpg in the repo for reference.