# Flat washer (ISO 7089, ISO 7091, ISO 7092, ISO 7093-1, DIN 9021, DIN 440 V, DIN 7349)

Metric plain washers in seven standard series, with catalogue sizes as presets.

## Geometry

A flat ring: hole **d1** (min = nominal), outside diameter **d2** (max = nominal), thickness **h** (nominal, the
middle of the standard's min and max). DIN 440 form V has a square hole of side **a** (min). ISO 7090's outer
chamfer is not part of this recipe. The washer lies on the XY plane at the origin, its thickness along +Z.

## Parameters

| Parameter | Meaning |
|---|---|
| `standard` | `ISO 7089` (= DIN 125-A, normal series), `ISO 7091` (= DIN 126, grade C), `ISO 7092` (= DIN 433, small series), `ISO 7093-1` (large series), `DIN 9021` (large, sizes ISO 7093-1 lacks), `DIN 440 V` (square hole), `DIN 7349` (heavy) |
| `size` | Bolt size the washer is for; each standard has its own sizes (tables below) |
| `material` | `steel` (zinc plated), `stainless-a2`, `stainless-a4` |

## Sources

Dimensions in mm, from the standards' tables as reproduced on fasten.it ("reproduced by permission of DIN") and
fasteners.eu; each table names its pages. Columns: d1, d2, h.

### ISO 7089:2000, Table 1 (DIN 125-1 form A has the same dimensions)

DIN EN ISO 7089:2000-11, <https://fasten.it/norms/norm/din_en_iso_7089>; <https://www.fasteners.eu/standards/ISO/7089/>.

| Size | d1 | d2 | h |
|---|---|---|---|
| M1.6 | 1.7 | 4 | 0.3 |
| M2 | 2.2 | 5 | 0.3 |
| M2.5 | 2.7 | 6 | 0.5 |
| M3 | 3.2 | 7 | 0.5 |
| M3.5 | 3.7 | 8 | 0.5 |
| M4 | 4.3 | 9 | 0.8 |
| M5 | 5.3 | 10 | 1 |
| M6 | 6.4 | 12 | 1.6 |
| M8 | 8.4 | 16 | 1.6 |
| M10 | 10.5 | 20 | 2 |
| M12 | 13 | 24 | 2.5 |
| M14 | 15 | 28 | 2.5 |
| M16 | 17 | 30 | 3 |
| M18 | 19 | 34 | 3 |
| M20 | 21 | 37 | 3 |
| M22 | 23 | 39 | 3 |
| M24 | 25 | 44 | 4 |
| M27 | 28 | 50 | 4 |
| M30 | 31 | 56 | 4 |
| M33 | 34 | 60 | 5 |
| M36 | 37 | 66 | 5 |

### ISO 7091:2000, Table 1 (DIN 126)

DIN EN ISO 7091:2000-11, <https://fasten.it/norms/norm/din_en_iso_7091>; <https://www.fasteners.eu/standards/ISO/7091/>.

| Size | d1 | d2 | h |
|---|---|---|---|
| M1.6 | 1.8 | 4 | 0.3 |
| M2 | 2.4 | 5 | 0.3 |
| M2.5 | 2.9 | 6 | 0.5 |
| M3 | 3.4 | 7 | 0.5 |
| M4 | 4.5 | 9 | 0.8 |
| M5 | 5.5 | 10 | 1 |
| M6 | 6.6 | 12 | 1.6 |
| M8 | 9 | 16 | 1.6 |
| M10 | 11 | 20 | 2 |
| M12 | 13.5 | 24 | 2.5 |
| M16 | 17.5 | 30 | 3 |
| M20 | 22 | 37 | 3 |
| M24 | 26 | 44 | 4 |
| M30 | 33 | 56 | 4 |
| M36 | 39 | 66 | 5 |
| M42 | 45 | 78 | 8 |
| M48 | 52 | 92 | 8 |
| M56 | 62 | 105 | 10 |
| M64 | 70 | 115 | 10 |

### ISO 7092:2000, Table 1 (DIN 433-1)

DIN EN ISO 7092:2000-11, <https://fasten.it/norms/norm/din_en_iso_7092>. M36 d2 is 60 (fasten.it's DIN EN ISO 7092 and DIN 433 tables,
and <https://www.jcfasteners.com/wp-content/uploads/ISO-7092-Small-OD-Washer-B6iD10-SS316.pdf>); fasteners.eu's 58 is
the outlier. ISO 7092 covers M1.6 to M36.

| Size | d1 | d2 | h |
|---|---|---|---|
| M1.6 | 1.7 | 3.5 | 0.3 |
| M2 | 2.2 | 4.5 | 0.3 |
| M2.5 | 2.7 | 5 | 0.5 |
| M3 | 3.2 | 6 | 0.5 |
| M3.5 | 3.7 | 7 | 0.5 |
| M4 | 4.3 | 8 | 0.5 |
| M5 | 5.3 | 9 | 1 |
| M6 | 6.4 | 11 | 1.6 |
| M8 | 8.4 | 15 | 1.6 |
| M10 | 10.5 | 18 | 1.6 |
| M12 | 13 | 20 | 2 |
| M14 | 15 | 24 | 2.5 |
| M16 | 17 | 28 | 2.5 |
| M18 | 19 | 30 | 2.5 |
| M20 | 21 | 34 | 3 |
| M24 | 25 | 39 | 4 |
| M30 | 31 | 50 | 4 |
| M36 | 37 | 60 | 5 |

### ISO 7093-1:2000, Table 1

DIN EN ISO 7093-1:2000-11, <https://fasten.it/norms/norm/din_en_iso_7093-1> (the only source found).

| Size | d1 | d2 | h |
|---|---|---|---|
| M3 | 3.2 | 9 | 0.8 |
| M3.5 | 3.7 | 11 | 0.8 |
| M4 | 4.3 | 12 | 1 |
| M5 | 5.3 | 15 | 1 |
| M6 | 6.4 | 18 | 1.6 |
| M8 | 8.4 | 24 | 2 |
| M10 | 10.5 | 30 | 2.5 |
| M12 | 13 | 37 | 3 |
| M14 | 15 | 44 | 3 |
| M16 | 17 | 50 | 3 |
| M18 | 19 | 56 | 4 |
| M20 | 21 | 60 | 4 |
| M22 | 23 | 66 | 5 |
| M24 | 25 | 72 | 5 |
| M27 | 30 | 85 | 6 |
| M30 | 33 | 92 | 6 |
| M33 | 36 | 105 | 6 |
| M36 | 39 | 110 | 8 |

### DIN 9021:1990-03 (only the sizes ISO 7093-1 lacks)

<https://fasten.it/norms/norm/din_9021>; <https://www.fasteners.eu/standards/DIN/9021/>.

| Size | d1 | d2 | h |
|---|---|---|---|
| M2.5 | 2.7 | 8 | 0.8 |
| M7 | 7.4 | 22 | 2 |

### DIN 440:2001-03 form V (square hole; h nominal = middle of h min and h max)

<https://fasten.it/norms/norm/din_440> (first table, form V).

| Size | a | d2 | h |
|---|---|---|---|
| M5 | 5.5 | 18 | 2 |
| M6 | 6.6 | 22 | 2 |
| M8 | 9 | 28 | 3 |
| M10 | 11 | 34 | 3 |
| M12 | 14 | 44 | 4 |
| M16 | 18 | 56 | 5 |
| M20 | 22 | 72 | 6 |
| M22 | 24 | 80 | 6 |

### DIN 433-1:1990-03 (the sizes below ISO 7092's range)

<https://fasten.it/norms/norm/din_433>.

| Size | d1 | d2 | h |
|---|---|---|---|
| M1 | 1.1 | 2.5 | 0.3 |
| M1.2 | 1.3 | 3 | 0.3 |
| M1.4 | 1.5 | 3 | 0.3 |

### DIN 7349:2009-08

<https://fasten.it/norms/norm/din_7349> (supersedes the 1974 edition); <https://www.fasteners.eu/standards/DIN/7349/>.

| Size | d1 | d2 | h |
|---|---|---|---|
| M3 | 3.2 | 9 | 1 |
| M4 | 4.3 | 12 | 1.6 |
| M5 | 5.3 | 15 | 2 |
| M6 | 6.4 | 17 | 3 |
| M8 | 8.4 | 21 | 4 |
| M10 | 10.5 | 25 | 4 |
| M12 | 13 | 30 | 6 |
| M14 | 15 | 36 | 6 |
| M16 | 17 | 40 | 6 |
| M18 | 19 | 44 | 8 |
| M20 | 21 | 44 | 8 |
| M22 | 23 | 50 | 8 |
| M24 | 25 | 50 | 10 |
| M27 | 28 | 60 | 10 |
| M30 | 31 | 68 | 10 |

Corrected in this audit: ISO 7092 M36 d2 58 -> 60; M1, M1.2 and M1.4 moved from "ISO 7092" (which starts at M1.6) to
DIN 433; DIN 7349 edition 1974 -> 2009-08 (same values).

Preset list: sizes of the step.parts catalogue (MIT), see `library/NOTICE.md`. Catalogue sizes outside these tables
have no preset (ISO 7090 M3; ISO 7091 / DIN 126 M3.5, M7, M14, M18, M22, M27, M33, M39, M45, M52, M60; ISO 7093 M2).