Bulletin d'étalonnage
Every board leaves measured.
Because the rest of the business already does this. A real one, for a real serial, with the arithmetic you can check.
Bulletin d'étalonnage
Calibration certificate · ENTREFER SA · Neuchâtel
ET87-2026-0412
Each key was driven to its mechanical stop and released through a full cycle on the bench named above. The flux at rest and at bottom-out was recorded, and the error at the 1.20 mm reference actuation point was computed against the nominal curve (10.13 mT → 251.47 mT).
30.8µm
spread, worst key to worst key
40µm
shipping limit
87
keys measured
PASS
released
Worst two keys: F3 +15.8 µm and Left +15.5 µm. If the spread had exceeded 40 µm the board would have gone back to the bench rather than into a box.
Error at the reference point, by key
Scroll sideways for the whole board →
0 to 40 µm of error. The two outlined keys are the worst on this board.
| Key | RestmT | BottommT | Errorµm |
|---|---|---|---|
| Esc | 10.28 | 260.56 | -10.4 |
| F1 | 9.95 | 240.39 | +13.3 |
| F2 | 10.29 | 261.00 | -10.9 |
| F3 | 9.92 | 238.45 | +15.8 |
| F4 | 10.05 | 246.37 | +6.0 |
| F5 | 10.11 | 250.40 | +1.3 |
| F6 | 10.05 | 246.37 | +6.0 |
| F7 | 10.03 | 245.03 | +7.7 |
| F8 | 10.30 | 262.11 | -12.1 |
| F9 | 9.93 | 239.08 | +15.0 |
| F10 | 10.06 | 247.12 | +5.1 |
| F11 | 10.33 | 263.85 | -14.0 |
| F12 | 9.98 | 242.55 | +10.7 |
| ` | 10.21 | 256.32 | -5.6 |
| 1 | 10.28 | 260.38 | -10.2 |
| 2 | 10.13 | 251.59 | -0.1 |
| 3 | 10.15 | 252.58 | -1.3 |
| 4 | 10.31 | 262.75 | -12.8 |
| 5 | 9.97 | 241.47 | +12.0 |
| 6 | 10.29 | 261.34 | -11.2 |
| 7 | 10.35 | 264.74 | -15.0 |
| 8 | 10.00 | 243.67 | +9.3 |
| 9 | 10.11 | 250.14 | +1.6 |
| 0 | 10.00 | 243.32 | +9.7 |
| - | 10.20 | 255.82 | -5.0 |
| = | 10.05 | 246.42 | +6.0 |
| Bksp | 10.03 | 245.26 | +7.4 |
| Tab | 10.27 | 259.80 | -9.5 |
| Q | 10.32 | 262.88 | -12.9 |
| W | 10.00 | 243.52 | +9.5 |
| E | 9.94 | 239.64 | +14.3 |
| R | 9.95 | 240.57 | +13.1 |
| T | 10.17 | 253.69 | -2.6 |
| Y | 9.99 | 242.59 | +10.6 |
| U | 9.99 | 243.03 | +10.1 |
| I | 9.94 | 239.89 | +14.0 |
| O | 10.13 | 251.62 | -0.2 |
| P | 9.99 | 243.10 | +10.0 |
| [ | 10.13 | 251.58 | -0.1 |
| ] | 10.06 | 247.36 | +4.9 |
| \ | 10.09 | 249.19 | +2.7 |
| Caps | 10.08 | 248.16 | +3.9 |
| A | 10.33 | 263.67 | -13.8 |
| S | 10.18 | 254.26 | -3.2 |
| D | 10.00 | 243.24 | +9.8 |
| F | 10.08 | 248.51 | +3.5 |
| G | 9.95 | 240.68 | +13.0 |
| H | 9.98 | 242.55 | +10.7 |
| J | 10.25 | 258.77 | -8.4 |
| K | 10.20 | 255.65 | -4.8 |
| L | 9.98 | 242.40 | +10.9 |
| ; | 10.20 | 255.58 | -4.8 |
| ' | 10.23 | 257.34 | -6.7 |
| Enter | 9.92 | 238.88 | +15.2 |
| Shift | 10.04 | 245.94 | +6.6 |
| Shift | 10.26 | 259.45 | -9.1 |
| Z | 10.27 | 259.75 | -9.5 |
| X | 10.24 | 257.90 | -7.4 |
| C | 10.31 | 262.81 | -12.9 |
| V | 9.93 | 239.05 | +15.0 |
| B | 9.97 | 241.40 | +12.1 |
| N | 10.31 | 262.38 | -12.4 |
| M | 10.23 | 257.30 | -6.7 |
| , | 10.21 | 255.99 | -5.2 |
| . | 10.01 | 244.27 | +8.6 |
| / | 10.17 | 253.84 | -2.7 |
| Ctrl | 9.93 | 239.11 | +14.9 |
| Ctrl | 9.98 | 242.09 | +11.2 |
| Win | 9.99 | 242.59 | +10.6 |
| Alt | 10.24 | 258.07 | -7.6 |
| Alt | 10.33 | 263.87 | -14.0 |
| Space | 10.17 | 253.64 | -2.5 |
| Fn | 10.13 | 251.61 | -0.2 |
| Menu | 10.25 | 258.96 | -8.6 |
| PrtSc | 10.29 | 261.54 | -11.5 |
| Scroll | 9.96 | 241.05 | +12.5 |
| Pause | 10.34 | 264.43 | -14.6 |
| Ins | 9.97 | 241.93 | +11.4 |
| Home | 10.06 | 247.38 | +4.8 |
| PgUp | 10.35 | 264.79 | -15.0 |
| Del | 10.18 | 254.58 | -3.6 |
| End | 10.10 | 249.54 | +2.3 |
| PgDn | 10.06 | 246.88 | +5.4 |
| Up | 10.32 | 262.88 | -12.9 |
| Left | 9.92 | 238.62 | +15.5 |
| Down | 10.05 | 246.67 | +5.7 |
| Right | 9.94 | 240.15 | +13.6 |
ENTREFER SA · Rue de la Maladière 24 · 2000 Neuchâtel · This certificate is generated from the field equation and a deterministic tolerance stack, at build time, from the serial above. It is not a record of a measurement of a physical object, because there is no physical object — see the note at the foot of the page.
What is being measured
Not the switch on its own. The number that matters is the whole stack: the depth the magnet sits at in the stem, the height of the plate above the board, the thickness of the gasket, and how far the socket lets the switch settle. All of it lands on one figure — the air gap at rest — and a few hundredths of a millimetre there moves the actuation point by micrometres.
Why 40 µm
Because it is roughly the point at which a fast typist starts to feel that one key is not like its neighbours. It is not a physical limit and we did not pick it because it is impressive; it is the number at which the boards we rejected stopped being boards anyone complained about.