# Walkie One 28 — R3.2 A prototype candidate

2026-09-11 · Prepared in Autodesk Fusion by Codex. No Adam service calls were used for this revision.

**This is a new development candidate for fit and functional testing. R3.1 remains the frozen print/RPS baseline. R3.2 A is not a production or casting release.** The outer shells retain their 78 × 150 × 24 mm combined envelope. The approved exterior, soft rim, orange grip, round play cap and lowered status light are preserved. Purchased parts, the selected antenna and the PCB location are retained.

## Open the model

- `cad/Walkie_One_28_R3_2_A_PTT_RF_PROTOTYPE.f3d` — complete native Autodesk Fusion candidate.
- `cad/Walkie_One_28_R3_2_A_REFERENCE_ASSEMBLY_NOT_FOR_PRODUCTION.step` — complete neutral-format reference assembly. STEP and STP are the same format.
- `cad/changed_parts/` — six changed/new fabricated parts, one STEP each.
- `print/changed_parts/` — corresponding six STL files, in millimetres. This is a replacement-parts set, not a complete printer project or complete device print kit. Reuse unchanged R3.1 parts.
- `renders/` — actual CAD inspection images; these are not inspiration renders.
- `documents/ASSEMBLY_AND_TEST_NOTES.md` — new hardware, assembly order and remaining tests.

## Change 1: guided press-to-talk carrier

The carrier now has two integral Ø2.4 mm pins in 24.7 mm long split guide bores. The front shell contains the front halves; two removable caps close the rear halves. This permits rear insertion of the carrier instead of trapping it in closed sleeves. The guides are at Y −12.5 and +25 mm, with axes at Z −8.8 and −7.8 mm respectively. Their nominal bore diameter is 2.6 mm, giving 0.2 mm diametral clearance. The lower guide is positioned to clear the microphone and LED keepers.

Two **new M2 × 5 pan-head fixing references** secure the guide caps. Each cap has a 2.2 mm clearance hole and registration features; the shell has a provisional 1.7 mm pilot. Screw thread geometry, resin engagement, torque and printed fits require qualification. These are not modeled metal threaded inserts.

The inherited replaceable contact, switch cassette, nominal 0.15 mm released contact gap and 0.45 mm stop travel remain. The actual LIDUOLE switch travel and return force are still unmeasured. The guides constrain imposed tilt earlier than the initial short-guide trial; a rigid tilt diagnostic is not a simulation of friction, flexibility, tolerance or real button return.

## Change 2: antenna cable integration

The selected **Taoglas FXUB63.07.0150C** remains in its existing planar position. Its full nominal 150 mm, Ø1.37 mm coax is now modeled, with a provisional PCB plug envelope at the cellular connector. The route uses an approximate feed position along the long edge, informed by the supplier mechanical drawing. The old short-tail reference is retained hidden as `SUPERSEDED...` in the native file and excluded from the assembly STEP.

The lower antenna frame now has a cable relief and a raised dielectric bridge to maintain a connected frame. The rear shell has a matching relief and two integral open cable saddles with lands for dielectric retaining tape. The model contains two 5 × 6 × 0.08 mm tape installation envelopes; tape selection, bond durability and retention are still to be tested.

The route was checked at **141, 150 and 159 mm**, spanning the supplier's ±9 mm lead-length tolerance. Hidden alternative routes and Ø2.2 mm routing envelopes are included in the native file for review. They are not extra physical cables or parts to manufacture. The selected 5 mm bend radius is a provisional layout choice, not a claimed supplier-approved minimum. The exact received feed bond, plug seating and cable bend limits must still be confirmed.

**The antenna metal-spacing issue remains open.** This revision does not claim that the manufacturer's ≥10 mm guidance is met, nor that cellular performance is proven. RF testing with the final metal grille/caps, populated PCB, battery and case is required. GNSS antenna/cable remain omitted.

## Verification completed

- Six modified/new fabricated bodies match their intended native geometry and reopen successfully from the saved F3D.
- The exported assembly contains 568 valid solids in an independent OpenCascade check.
- All six changed-part STEP files contain one valid solid; all six STL files are watertight with consistent winding.
- Independent STEP checks found no positive overlap of the PTT carrier with the front shell, rear shell or guide caps at 0, 0.15, 0.225, 0.40 and 0.45 mm straight travel.
- New pin insertion from the rear was sampled with caps removed. The added guides do not obstruct that path. This is not a simulation of the entire assembly sequence.
- Changed geometry was checked against existing component solids and the inherited estimated terminal/solder envelopes. Cable routes at all three tested lengths clear modeled parts with the revised supports installed.
- New-part pair checks found only the intentional screw/pilot engagement proxies and cable/plug envelope overlap.
- Shell bounds and checked exterior layers are unchanged. Frozen R3.1 native/STEP SHA-256 values are unchanged.

Precise STEP/native volume comparisons use adaptive OpenCascade integration and Fusion's Very High calculation accuracy, with a relative comparison tolerance of 0.001%. Default low-accuracy volume values are also retained in the raw native inventories; small integration differences are not dimensional tolerances.

Evidence: `verification/independent_export_validation.json`, `reopened_native_verification.json`, `ptt_trial.json`, `ptt_verification.json`, `support_trial.json`, `exterior_preservation.json` and `new_part_pair_check.json`.

## Revision boundary

Changed fabricated parts are the front shell, rear shell, PTT carrier and lower LTE frame, plus the two new guide caps. All other fabricated parts retain their existing status and geometry. The missing detailed U6 model, physical switch measurements, full wiring/connector installation, acoustics, light performance, resin/thread choices and RF testing remain open. The public R3.1 handoff and files already prepared for Max have not been replaced by this candidate.