# Hex keys (Allen keys): ISO 2936 metric 0.7–36 mm and ASME B18.3 inch .050–7/8 in: across flats, across corners, long and short arm + 31 key models

> How long are hex keys, and what are the across-flats and across-corners sizes of a 2, 3, 4, 5, 6, 8, 10 mm or 1/8, 3/16, 1/4 in Allen key?

- Category: Hardware › Hand tool interfaces
- Kind: Standard part
- Basis: ISO 2936:2001 Table 1 (free sample), the ISO 2936:1995 table beside it, and the ANSI B18.3 inch key tables of Alma Bolt and AFT Fasteners; key models are Xem-drawn from those numbers
- Page: https://xemstudio.com/objects/hex-keys-iso-2936-asme-b18-3/ · JSON: https://xemstudio.com/api/geometry?object=hex-keys-iso-2936-asme-b18-3 · Plain text: https://xemstudio.com/objects/hex-keys-iso-2936-asme-b18-3/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
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## Overall (mm)

| length | width | height |
|---|---|---|
| 184.1 | 54.0 | 21.8 |

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- A hex key (Allen key, Allen wrench, hex wrench, L-key) is a hexagonal bar bent to an L. The hexagon is the size of the screw socket (s, across flats); the long arm (l1) gives reach and the short arm (l2) gives torque. ISO 2936 lists s from 0.7 to 36 mm with e (across corners), l1 in a standard, a long and an extra-long series, and l2 (short arm). Metric rows in the table are the ISO 2936:2001 values: s min is the lower limit (s max equals s nominal), and e max / e min are the across-corners limits. The 'ISO 2936:1995' column shows the l1 / l2 that edition prints for the same s, because the two editions differ (for example s = 2 mm: 50 / 16 in 1995, 52 / 18 in 2001; s = 5 mm: 80 / 28 against 85 / 33). The 1995 sample as read lists fewer sizes than the 2001 table (no 3.5, 4.5, 7, 9, 11, 13, 15, 16, 18, 21, 23, 29 or 30 mm rows). ISO 2936:2014 (sixth edition, a minor revision of 2001 per the iTeh catalogue) is the current edition; its free sample shows only fragments of Table 1, so the 2001 numbers are used and the models follow them. A copy of the 2001 table on amesweb gives the same values for s = 2, 5, 10, 19 and 36. Check the key you hold: makers do not all follow the same series.
- Inch rows follow ANSI B18.3 as printed by two sources that agree to within 0.001 in on every size used: Alma Bolt's table (min / max for both arms, midpoints equal AFT's nominals) and AFT Fasteners' short-arm and long-arm SAE tables. Sizes .028, .035 and 1 in are left out: the Alma .035 row is out of sequence (long arm larger than the .050 row), and the AFT 1 in row repeats the .050 numbers. AFT's 1/2 in minimum width is mistyped in the source and is not used. The 'long series' column (AFT only) is the longer-arm key sold in the same sizes. Across corners e max is Alma's value. The 'mm' of the inch rows are inch × 25.4 and are computed here.
- Models: all 31 files are Xem-drawn from the numbers above: a hexagon of the key's across-flats size with each corner rounded to the e max circle, swept along an L with arms l1 and l2 measured as overall extents (tip of the long arm at one end, outer face of the short arm at the other). The bend radius is an Xem choice, 2 × s on the centre line, because no source read gives it. Metric models use the 2001 'standard' l1 and l2 for s = 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10, 12, 14, 17 and 19 mm; inch models use the short-arm series for .050 to 3/4 in. Models carry no markings, ball ends or hardness details. A key holder or drill-through rack needs the hexagon (across corners e max) for the slot and l1 / l2 for the length.
- Not here: Torx, Pozidriv, Phillips, spline and tamper-proof keys; T-handle and folding sets; ball-end geometry; the 2014 edition's changes if any; tolerances on arm length (the standard has them, the sample reads only partly).

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| key hexagon s | metric 1.5 to 19 mm across flats (s max = nominal; s min in the table); inch .050 to 3/4 in | hexagon socket in a cap screw or set screw of the same nominal size (socket-head-cap-screws-metric, socket-set-screws-inch-asme-b18-3): the key hexagon is the male, the screw's socket the female | slide | hexkey-* |
| key corners e max | e max 1.68 to 21.63 mm (metric, 1.5 to 19); across corners of the model | slot or pocket in a key holder or rack: clear e max and add your process allowance to the slot | slide | hexkey-* |
| long and short arm | l1 and l2 from the table (e.g. 85 / 33 mm for s = 5) | holder pocket depth or rack hole: the length of the arm that goes in | designed | hexkey-* |

## Sizes

| type | s across flats (mm) | s min (mm) | e across corners max (mm) | e min (mm) | l1 long arm standard (mm) | l1 long series (mm) | l1 extra-long (mm) | l2 short arm (mm) | ISO 2936:1995 l1 / l2 (mm) |
|---|---|---|---|---|---|---|---|---|---|
| metric | 0.7 | 0.70 | 0.79 | 0.76 | 33 | — | — | 7 | 32 / 6 |
| metric | 0.9 | 0.88 | 0.99 | 0.96 | 33 | — | — | 11 | 32 / 10 |
| metric | 1.3 | 1.24 | 1.42 | 1.37 | 41 | 63.5 | 81 | 13 | 40 / 12 |
| metric | 1.5 | 1.48 | 1.68 | 1.63 | 46.5 | 63.5 | 91.5 | 15.5 | 45 / 14 |
| metric | 2 | 1.96 | 2.25 | 2.18 | 52 | 77 | 102 | 18 | 50 / 16 |
| metric | 2.5 | 2.46 | 2.82 | 2.75 | 58.5 | 87.5 | 114.5 | 20.5 | 56 / 18 |
| metric | 3 | 2.96 | 3.39 | 3.31 | 66 | 93 | 129 | 23 | 63 / 20 |
| metric | 3.5 | 3.45 | 3.96 | 3.91 | 69.5 | 98.5 | 140 | 25.5 | — |
| metric | 4 | 3.95 | 4.53 | 4.44 | 74 | 104 | 144 | 29 | 70 / 25 |
| metric | 4.5 | 4.45 | 5.10 | 5.04 | 80 | 114.5 | 156 | 30.5 | — |
| metric | 5 | 4.95 | 5.67 | 5.58 | 85 | 120 | 165 | 33 | 80 / 28 |
| metric | 6 | 5.95 | 6.81 | 6.71 | 96 | 141 | 186 | 38 | 90 / 32 |
| metric | 7 | 6.94 | 7.94 | 7.85 | 102 | 147 | 197 | 41 | — |
| metric | 8 | 7.94 | 9.09 | 8.97 | 108 | 158 | 208 | 44 | 100 / 36 |
| metric | 9 | 8.94 | 10.23 | 10.10 | 114 | 169 | 219 | 47 | — |
| metric | 10 | 9.94 | 11.37 | 11.23 | 122 | 180 | 234 | 50 | 112 / 40 |
| metric | 11 | 10.89 | 12.51 | 12.31 | 129 | 191 | 247 | 53 | — |
| metric | 12 | 11.89 | 13.65 | 13.44 | 137 | 202 | 262 | 57 | 125 / 45 |
| metric | 13 | 12.89 | 14.79 | 14.56 | 145 | 213 | 277 | 63 | — |
| metric | 14 | 13.89 | 15.93 | 15.70 | 154 | 229 | 294 | 70 | 140 / 56 |
| metric | 15 | 14.89 | 17.07 | 16.83 | 161 | 240 | 307 | 73 | — |
| metric | 16 | 15.89 | 18.21 | 17.97 | 168 | 240 | 307 | 76 | — |
| metric | 17 | 16.89 | 19.35 | 19.09 | 177 | 262 | 337 | 80 | 160 / 63 |
| metric | 18 | 17.89 | 20.49 | 20.21 | 188 | 262 | 358 | 84 | — |
| metric | 19 | 18.87 | 21.63 | 21.32 | 199 | — | — | 89 | 180 / 70 |
| metric | 21 | 20.87 | 23.91 | 23.58 | 211 | — | — | 96 | — |
| metric | 22 | 21.87 | 25.05 | 24.71 | 222 | — | — | 102 | 200 / 80 |
| metric | 23 | 22.87 | 26.16 | 25.86 | 233 | — | — | 108 | — |
| metric | 24 | 23.87 | 27.33 | 26.97 | 248 | — | — | 114 | 224 / 90 |
| metric | 27 | 26.87 | 30.75 | 30.36 | 277 | — | — | 127 | 250 / 100 |
| metric | 29 | 28.87 | 33.03 | 32.59 | 311 | — | — | 141 | — |
| metric | 30 | 29.87 | 34.17 | 33.75 | 315 | — | — | 142 | — |
| metric | 32 | 31.84 | 36.45 | 35.98 | 347 | — | — | 157 | 315 / 125 |
| metric | 36 | 35.84 | 41.01 | 40.50 | 391 | — | — | 176 | 355 / 140 |
| inch | .050 in = 1.270 | — | 1.42 (0.0560 in) | — | 42.1 (1.656 in) | 72.2 (2.844 in) | — | 13.5 (0.531 in) | — |
| inch | 1/16 in = 1.587 | — | 1.78 (0.0701 in) | — | 44.4 (1.750 in) | 76.2 (3.000 in) | — | 14.3 (0.562 in) | — |
| inch | 5/64 in = 1.984 | — | 2.24 (0.0880 in) | — | 47.6 (1.875 in) | 81.0 (3.188 in) | — | 15.5 (0.609 in) | — |
| inch | 3/32 in = 2.381 | — | 2.69 (0.1058 in) | — | 50.8 (2.000 in) | 85.7 (3.375 in) | — | 16.7 (0.656 in) | — |
| inch | 7/64 in = 2.778 | — | 3.14 (0.1238 in) | — | 54.0 (2.125 in) | 90.5 (3.562 in) | — | 17.9 (0.703 in) | — |
| inch | 1/8 in = 3.175 | — | 3.60 (0.1418 in) | — | 57.1 (2.250 in) | 95.2 (3.750 in) | — | 19.0 (0.750 in) | — |
| inch | 9/64 in = 3.572 | — | 4.05 (0.1593 in) | — | 60.3 (2.375 in) | 100.0 (3.937 in) | — | 20.2 (0.796 in) | — |
| inch | 5/32 in = 3.969 | — | 4.51 (0.1774 in) | — | 63.5 (2.500 in) | 104.8 (4.125 in) | — | 21.4 (0.844 in) | — |
| inch | 3/16 in = 4.762 | — | 5.42 (0.2135 in) | — | 69.8 (2.750 in) | 114.3 (4.500 in) | — | 23.8 (0.938 in) | — |
| inch | 7/32 in = 5.556 | — | 6.32 (0.2490 in) | — | 76.2 (3.000 in) | 123.8 (4.875 in) | — | 26.2 (1.031 in) | — |
| inch | 1/4 in = 6.350 | — | 7.23 (0.2845 in) | — | 82.5 (3.250 in) | 133.3 (5.250 in) | — | 28.6 (1.125 in) | — |
| inch | 5/16 in = 7.938 | — | 9.07 (0.3570 in) | — | 95.2 (3.750 in) | 152.4 (6.000 in) | — | 31.8 (1.250 in) | — |
| inch | 3/8 in = 9.525 | — | 10.88 (0.4285 in) | — | 107.9 (4.250 in) | 171.4 (6.750 in) | — | 34.9 (1.375 in) | — |
| inch | 7/16 in = 11.112 | — | 12.71 (0.5005 in) | — | 120.6 (4.750 in) | 190.5 (7.500 in) | — | 38.1 (1.500 in) | — |
| inch | 1/2 in = 12.700 | — | 14.52 (0.5715 in) | — | 133.3 (5.250 in) | 209.5 (8.250 in) | — | 41.3 (1.625 in) | — |
| inch | 9/16 in = 14.287 | — | 16.31 (0.6420 in) | — | 146.0 (5.750 in) | 228.6 (9.000 in) | — | 44.4 (1.750 in) | — |
| inch | 5/8 in = 15.875 | — | 18.15 (0.7146 in) | — | 158.8 (6.250 in) | 247.6 (9.750 in) | — | 47.6 (1.875 in) | — |
| inch | 3/4 in = 19.050 | — | 21.79 (0.8580 in) | — | 184.1 (7.250 in) | 285.8 (11.250 in) | — | 54.0 (2.125 in) | — |
| inch | 7/8 in = 22.225 | — | 25.45 (1.0020 in) | — | 209.5 (8.250 in) | 323.8 (12.750 in) | — | 60.3 (2.375 in) | — |

## Where the files are

- ISO (iTeh Standards free sample): [ISO 2936:2001 hexagon socket screw keys, Table 1: s, e, l1 (standard / long / extra-long), l2, 0.7 to 36 mm](https://cdn.standards.iteh.ai/samples/29090/080c7c518b534653b3445e6c9b77c85b/ISO-2936-2001.pdf) — web — Standards body sample pages; dimensions are facts
- ISO (iTeh Standards free sample): [ISO 2936:1995 hexagon socket screw keys, Table 1: s, e, l1, l2 (one arm-length series)](https://cdn.standards.iteh.ai/samples/21908/bf1c340366614798bc8c229fedc9f5b5/ISO-2936-1995.pdf) — web — Standards body sample pages; dimensions are facts
- ISO (iTeh Standards catalogue): [ISO 2936:2014 (sixth edition, minor revision of 2001): scope and edition information](https://standards.iteh.ai/catalog/standards/iso/87f964f2-b08f-42b8-876f-59beb1ad71c8/iso-2936-2014) — web — Standards body catalogue entry
- amesweb: [Hexagon socket screw key chart (copy of the ISO 2936:2001 table; rows 2, 5, 10, 19, 36 checked)](https://amesweb.info/Tools/Hexagon-Socket-Screw-Key-Chart.aspx) — web — Publisher's page; dimensions are facts
- Alma Bolt: [Hex keys meeting ANSI B18.3 and GGG-K-275: nominal size, across corners, short and long arm (max / min), .028 to 1 in](https://almabolt.com/pages/catalog/hardware/hexkeys.htm) — web — Publisher's page; dimensions are facts
- AFT Fasteners: [Short Arm and Long Arm SAE hex key dimensions: size, width across flats, long arm, short arm](https://aftfasteners.com/allen-wrench-sizes-dimensions) — web — Publisher's page; dimensions are facts
- McMaster-Carr: [L-keys, ISO 2936 filter (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/l-keys/specifications-met~iso-2936/) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)

## Free STEP/STL (31 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/index.json

- hexkey-iso2936-s1-5: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s1-5.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s1-5.stl) — ISO 2936:2001 hex key s = 1.5 mm across flats, corners rounded to e max 1.68 mm, long arm l1 = 46.5 mm, short arm l2 = 15.5 mm (overall extents to the outer face of the other arm); bend centre-line radius 3 mm is an Xem choice
- hexkey-iso2936-s2: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s2.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s2.stl) — ISO 2936:2001 hex key s = 2 mm across flats, corners rounded to e max 2.25 mm, long arm l1 = 52 mm, short arm l2 = 18 mm (overall extents to the outer face of the other arm); bend centre-line radius 4 mm is an Xem choice
- hexkey-iso2936-s2-5: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s2-5.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s2-5.stl) — ISO 2936:2001 hex key s = 2.5 mm across flats, corners rounded to e max 2.82 mm, long arm l1 = 58.5 mm, short arm l2 = 20.5 mm (overall extents to the outer face of the other arm); bend centre-line radius 5 mm is an Xem choice
- hexkey-iso2936-s3: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s3.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s3.stl) — ISO 2936:2001 hex key s = 3 mm across flats, corners rounded to e max 3.39 mm, long arm l1 = 66 mm, short arm l2 = 23 mm (overall extents to the outer face of the other arm); bend centre-line radius 6 mm is an Xem choice
- hexkey-iso2936-s4: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s4.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s4.stl) — ISO 2936:2001 hex key s = 4 mm across flats, corners rounded to e max 4.53 mm, long arm l1 = 74 mm, short arm l2 = 29 mm (overall extents to the outer face of the other arm); bend centre-line radius 8 mm is an Xem choice
- hexkey-iso2936-s5: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s5.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s5.stl) — ISO 2936:2001 hex key s = 5 mm across flats, corners rounded to e max 5.67 mm, long arm l1 = 85 mm, short arm l2 = 33 mm (overall extents to the outer face of the other arm); bend centre-line radius 10 mm is an Xem choice
- hexkey-iso2936-s6: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s6.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s6.stl) — ISO 2936:2001 hex key s = 6 mm across flats, corners rounded to e max 6.81 mm, long arm l1 = 96 mm, short arm l2 = 38 mm (overall extents to the outer face of the other arm); bend centre-line radius 12 mm is an Xem choice
- hexkey-iso2936-s8: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s8.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s8.stl) — ISO 2936:2001 hex key s = 8 mm across flats, corners rounded to e max 9.09 mm, long arm l1 = 108 mm, short arm l2 = 44 mm (overall extents to the outer face of the other arm); bend centre-line radius 16 mm is an Xem choice
- hexkey-iso2936-s10: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s10.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s10.stl) — ISO 2936:2001 hex key s = 10 mm across flats, corners rounded to e max 11.37 mm, long arm l1 = 122 mm, short arm l2 = 50 mm (overall extents to the outer face of the other arm); bend centre-line radius 20 mm is an Xem choice
- hexkey-iso2936-s12: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s12.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s12.stl) — ISO 2936:2001 hex key s = 12 mm across flats, corners rounded to e max 13.65 mm, long arm l1 = 137 mm, short arm l2 = 57 mm (overall extents to the outer face of the other arm); bend centre-line radius 24 mm is an Xem choice
- hexkey-iso2936-s14: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s14.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s14.stl) — ISO 2936:2001 hex key s = 14 mm across flats, corners rounded to e max 15.93 mm, long arm l1 = 154 mm, short arm l2 = 70 mm (overall extents to the outer face of the other arm); bend centre-line radius 28 mm is an Xem choice
- hexkey-iso2936-s17: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s17.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s17.stl) — ISO 2936:2001 hex key s = 17 mm across flats, corners rounded to e max 19.35 mm, long arm l1 = 177 mm, short arm l2 = 80 mm (overall extents to the outer face of the other arm); bend centre-line radius 34 mm is an Xem choice
- hexkey-iso2936-s19: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s19.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-iso2936-s19.stl) — ISO 2936:2001 hex key s = 19 mm across flats, corners rounded to e max 21.63 mm, long arm l1 = 199 mm, short arm l2 = 89 mm (overall extents to the outer face of the other arm); bend centre-line radius 38 mm is an Xem choice
- hexkey-asme-b18-3-050in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-050in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-050in.stl) — inch hex key .050 in across flats (1.270 mm), e max 1.422 mm, long arm 1.656 in, short arm 0.531 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-1-16in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-1-16in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-1-16in.stl) — inch hex key 1/16 in across flats (1.587 mm), e max 1.781 mm, long arm 1.75 in, short arm 0.562 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-5-64in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-5-64in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-5-64in.stl) — inch hex key 5/64 in across flats (1.984 mm), e max 2.235 mm, long arm 1.875 in, short arm 0.609 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-3-32in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-3-32in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-3-32in.stl) — inch hex key 3/32 in across flats (2.381 mm), e max 2.687 mm, long arm 2.0 in, short arm 0.656 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-7-64in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-7-64in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-7-64in.stl) — inch hex key 7/64 in across flats (2.778 mm), e max 3.145 mm, long arm 2.125 in, short arm 0.703 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-1-8in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-1-8in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-1-8in.stl) — inch hex key 1/8 in across flats (3.175 mm), e max 3.602 mm, long arm 2.25 in, short arm 0.75 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-9-64in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-9-64in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-9-64in.stl) — inch hex key 9/64 in across flats (3.572 mm), e max 4.046 mm, long arm 2.375 in, short arm 0.796 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-5-32in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-5-32in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-5-32in.stl) — inch hex key 5/32 in across flats (3.969 mm), e max 4.506 mm, long arm 2.5 in, short arm 0.844 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-3-16in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-3-16in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-3-16in.stl) — inch hex key 3/16 in across flats (4.762 mm), e max 5.423 mm, long arm 2.75 in, short arm 0.938 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-7-32in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-7-32in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-7-32in.stl) — inch hex key 7/32 in across flats (5.556 mm), e max 6.325 mm, long arm 3.0 in, short arm 1.031 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-1-4in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-1-4in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-1-4in.stl) — inch hex key 1/4 in across flats (6.350 mm), e max 7.226 mm, long arm 3.25 in, short arm 1.125 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-5-16in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-5-16in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-5-16in.stl) — inch hex key 5/16 in across flats (7.938 mm), e max 9.068 mm, long arm 3.75 in, short arm 1.25 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-3-8in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-3-8in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-3-8in.stl) — inch hex key 3/8 in across flats (9.525 mm), e max 10.884 mm, long arm 4.25 in, short arm 1.375 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-7-16in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-7-16in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-7-16in.stl) — inch hex key 7/16 in across flats (11.112 mm), e max 12.713 mm, long arm 4.75 in, short arm 1.5 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-1-2in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-1-2in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-1-2in.stl) — inch hex key 1/2 in across flats (12.700 mm), e max 14.516 mm, long arm 5.25 in, short arm 1.625 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-9-16in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-9-16in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-9-16in.stl) — inch hex key 9/16 in across flats (14.287 mm), e max 16.307 mm, long arm 5.75 in, short arm 1.75 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-5-8in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-5-8in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-5-8in.stl) — inch hex key 5/8 in across flats (15.875 mm), e max 18.151 mm, long arm 6.25 in, short arm 1.875 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice
- hexkey-asme-b18-3-3-4in: [STEP](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-3-4in.step) · [STL](https://xemstudio.com/files/hardware/hex-keys-iso-2936-asme-b18-3/hexkey-asme-b18-3-3-4in.stl) — inch hex key 3/4 in across flats (19.050 mm), e max 21.793 mm, long arm 7.25 in, short arm 2.125 in, short-arm series (ANSI B18.3, Alma Bolt / AFT); bend centre-line radius 2 x s is an Xem choice

## Questions

**How long is a 5 mm hex key?**

ISO 2936:2001 gives a long arm of 85 mm and a short arm of 33 mm (the 1995 edition printed 80 and 28).

**What is the across-corners size of a 4 mm hex key?**

4.53 mm maximum and 4.44 mm minimum in ISO 2936:2001, so a holder slot must clear 4.53 mm.

**How long is a 3/16 in Allen key?**

ANSI B18.3 short-arm series: long arm 2.750 in, short arm 0.938 in; the long series has a 4.500 in long arm.

**Is there a free STEP of a hex key?**

Yes: 31 Xem-drawn keys here, 13 metric (1.5 to 19 mm) and 18 inch (.050 to 3/4 in), with an Xem-chosen bend radius.

## Fits with

- [Socket head cap screws, M2–M8 (ISO 4762 / DIN 912)](https://xemstudio.com/objects/socket-head-cap-screws-metric/)
- [Socket head cap screws, inch #0 to 1-1/2 (ASME B18.3): head, hex socket, key engagement — full size table + models #0 to 1](https://xemstudio.com/objects/socket-head-cap-screws-inch-full/)
- [Socket set screws, inch (ASME B18.3), cup point: hex key size, cup and flat point diameter, shortest length #0 to 1](https://xemstudio.com/objects/socket-set-screws-inch-asme-b18-3/)
- [Shoulder screws ISO 7379 (metric): shoulder Ø, thread, head size, hex key, thread length, M5 to M20](https://xemstudio.com/objects/shoulder-screws-iso-7379/)
- [Shoulder screws ASME B18.3 (inch): shoulder Ø 1/4 to 3/4 in, thread, head size, hex key, thread length](https://xemstudio.com/objects/shoulder-screws-asme-b18-3/)
- [Hex bit shank 1/4 in (ISO 1173 C 6.3 and E 6.3): across flats 6.35 mm, across corners 7.18 mm, form C and E dimensions, 4–12.5 mm sizes + hex pocket gauge](https://xemstudio.com/objects/hex-bit-shank-iso-1173-1-4-in/)
- [Square drive sizes ISO 1174: 1/4, 3/8, 1/2, 3/4, 1 in drive (6.3, 10, 12.5, 20, 25 mm): male and female square limits + stub rail and pocket plate](https://xemstudio.com/objects/square-drive-iso-1174-1-4-to-1-in/)