# The core

Some things are print-tested on real walls. A design uses them as they are.

## Core bricks

Every brick below is core: it engages the wall, joins two printed parts or is a calibration piece. Its geometry changes only by a reviewed pull request, and any change to it is a new major version, so designs pinned to the old one keep building as tested.

- `calibration`: Calibration kit. Print-tested: Slot gauge and lock test (v11, 3 Oct 2026; archive/prototype/HISTORY.md §1).
- `cam-lock-mount`: Cam-lock mount. Print-tested: Quarter-turn cam lock with internal stops and guide: key 9.40 → 9.80 mm, peak 9.88 mm at 76°, 0.15 mm bore clearance, 0.3 mm end gaps, 1.9 × 6 mm lug (v11 lock test, 3 Oct 2026; HISTORY.md §1); Roll-in top L with the rounded heel (v04–v11 test prints; HISTORY.md §1).
- `cam-tuning`: Cam-lock tuning plate.
- `clip-label`: Clip label. Print-tested: 2 mm label plate (archive/prototype/README.md, Status).
- `cradle`: Wide cradle.
- `dovetail-slide`: Dovetail slide.
- `drop-dovetail`: Drop-in dovetail.
- `hook-arm`: Hook arm.
- `label-clip`: Label clips. Print-tested: This brick draws no plate. A 2 mm label plate is print-tested (archive/prototype/README.md, Status). The hooked dovetail, 4.5 mm clips and wedges are software-tested only..
- `multi-slot-lock`: Multi-slot lock.
- `press-in-holder`: Press-in label holders.
- `press-in-label`: Press-in label.
- `shelf-bracket`: Shelf bracket.
- `top-wedge`: Top wedge.

## Print-tested numbers

These come from real test prints. A design never types them; they are here so you know what the bricks hold fixed:

- The Standard printer fit: `fit.dovetail` 0.1 mm, `fit.print_in_place` 0.3 mm, `fit.bore` 0.15 mm and `fit.axial` 0.3 mm.
- The cam lock's grip once locked: 0.22 mm over the slot. The key goes in with 0.18 mm to spare, and the guide beside it is as tall.

The print-tested lock profile is fixed: its shape and these defaults are what was test-printed. The cam-lock bricks also have expert lock settings, with ranges, so the lock can be tuned to a wall:

| Setting             | Label                     | Group              | Range                     | Default |
| ------------------- | ------------------------- | ------------------ | ------------------------- | ------- |
| `unlock_vs_slot`    | Key height, unlocked      | Lock feel          | -0.78–0.02 mm (step 0.01) | -0.18   |
| `lock_vs_slot`      | Key height, locked        | Lock feel          | -0.18–0.62 mm (step 0.01) | 0.22    |
| `peak_vs_slot`      | Key height at the click   | Lock feel          | -0.18–0.82 mm (step 0.01) | 0.3     |
| `peak_angle`        | Click position            | Lock feel          | 60–84 ° (step 1)          | 76      |
| `flat_half`         | Click width               | Lock feel          | 3–10 ° (step 1)           | 6       |
| `guide_vs_slot`     | Guide tongue height       | Fit and clearances | -0.78–0.02 mm (step 0.01) | -0.18   |
| `guide_gap`         | Gap between key and guide | Fit and clearances | 0.15–0.8 mm (step 0.01)   | 0.3     |
| `side_skin`         | Cover over the key's side | Fit and clearances | 0–2 mm (step 0.1)         | 1       |
| `lug_r`             | Stop tab reach            | Key stops          | 5.2–7 mm (step 0.1)       | 6.2     |
| `lug_half`          | Stop tab width            | Key stops          | 10–30 ° (step 1)          | 20      |
| `lug_len`           | Stop tab length           | Key stops          | 3–8 mm (step 0.1)         | 6       |
| `lock_overtravel`   | Turn past locked          | Key stops          | 0–6 ° (step 0.5)          | 1.5     |
| `unlock_overtravel` | Turn back past unlocked   | Key stops          | 2–10 ° (step 0.5)         | 5       |

These are the `cam-lock-mount`'s; `cradle`, `hook-arm` and `shelf-bracket` have the same ones.

Leave them at their defaults. Change one only when an engagement fix names it (a fit row's note, or an R4 issue on the draft's wall), by the amount the fix says; never expose one as simple. Then tell the person to print the lock test on that wall before trusting it.

The wall data (every preset's numbers) and the printer-fit presets are core too.

## Asking for a new core piece

If a design needs geometry no brick gives (a new joint, a new kind of mount), don't fake it with shapes in the wall or by moving a mount's parts. Tell the person what is missing and why, in plain words: core pieces are added by the Slatfinity team, reviewed and test-printed first.