# Parallel key (DIN 6885-1)

Form A parallel key: both ends rounded, for a keyed shaft and hub.

## Geometry

A slot outline of width `b` and overall `length`, extruded to height `h`. Length along X, width along Y, base on the
XY plane, centred on the origin.

## Source

DIN 6885-1:1968 (withdrawn, still the common designation), key width b and height h, as listed at
<https://fasten.it/en/norms/norm/din_6885-1>.

| b × h | 2×2 | 3×3 | 4×4 | 5×5 | 6×6 | 8×7 | 10×8 | 12×8 |
|---|---|---|---|---|---|---|---|---|
| Shaft over … to | 6–8 | 8–10 | 10–12 | 12–17 | 17–22 | 22–30 | 30–38 | 38–44 |

No tolerance is stated: the source above lists none.

Preset lengths come from the step.parts catalogue metadata (MIT, `library/NOTICE.md`).