# Low-head socket cap screws: DIN 7984 M3–M20 and DIN 6912 (pilot recess) M4–M36 — head diameter and height, hex socket, thread length + head envelope models

> What are the head size, height and hex key size of a DIN 7984 or DIN 6912 low-head socket cap screw?

- Category: Hardware › Fasteners
- Kind: Standard part
- Basis: Westfield Fasteners' DIN 7984 table (cross-checked against Ferrofast), fasten.it's DIN 6912 table (03-2021, Aspen Fasteners' table as a cross-check); seven DIN 7984 head envelopes as files
- Page: https://xemstudio.com/objects/low-head-socket-cap-screws-din-7984-6912/ · JSON: https://xemstudio.com/api/geometry?object=low-head-socket-cap-screws-din-7984-6912 · Plain text: https://xemstudio.com/objects/low-head-socket-cap-screws-din-7984-6912/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 |
|---|---|---|
| 5.5 | 5.5 | 14.0 |

**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

- DIN 7984 (hexagon socket cap screws with low head, M3 to M20 here; the page lists to M24) in mm, from Westfield: pitch P; minimum thread length b for screws up to 125 mm long (b is longer for screws over 125 mm; the Westfield table has two more rows for that, not tabulated here); head diameter dk max / min; head height k max / min; socket s (nominal, with min / max on the source page) and socket depth t nominal (min – max); also shank ds, bearing face dw min, key corner e min, transition da max, edge radius r min, lf max and v max. The loadability of the low head is lower (Westfield: typically about 80 % of a standard 10.9 screw's); no strength values are tabulated here.
- Ferrofast's DIN 7984 table agrees with Westfield on dk, s, t and the other k values, but prints k max 6.5 for M10 (Westfield 6.0), alongside a k min of 5.82 which cannot go with 6.5, and a key size s max of 12.212 for M18 below its s min; those two entries are treated as errors and Westfield's values are used. fasten.it's DIN 6912 table prints k max 6.5 at M10, the same as Ferrofast's 7984 row; the DIN 7984 value could be the older figure. Use the edition your drawing cites.
- DIN 6912 (low head, with pilot recess) in the 03-2021 edition on fasten.it, M4 to M36, mm: P; b for three length ranges (≤ 125, > 125 to 200, > 200); dk max; k max; s nominal (socket); e min; dh min (the page's letter, read from the pilot-recess description as the recess diameter; not defined there); t1 nominal and t2 min (not defined either: socket and recess depths). The page says the 06-2009 edition has identical values, and that these screws have a short unthreaded portion of shank to make up for the pilot recess and a reduced loadability. Aspen's DIN 6912 sheet agrees on dk, k, s and the t values, but prints a dk min of 65.61 for M24 and a ds min of 65.61 for M36 (clearly errors, not used) and says it was compiled from public sources. Sizes in brackets in some sources (M14, M18, M22, M27, M33) are non-preferred.
- Files: DIN 7984 M3 to M12 head envelopes: a plain cylinder of diameter dk max and height k max with a flat-bottomed hex socket of the nominal s across flats and depth t nominal, on a plain shank at the nominal diameter. The length under the head is 4 × d (12 to 48 mm), Xem's example, not a published length. No thread, no head edge radius, no conical socket bottom. No DIN 6912 file: the pilot-recess dimensions (dh, t1, t2) are not defined in the sources read.
- McMaster-Carr sells pilot-recess (DIN 6912) screws and low-head socket screws with per-part STEP; its DIN 6912 and pilot-recess pages are linked, not copied. Standard-height socket screws: socket-head-cap-screws-metric, socket-head-cap-screws-inch-full.

## 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 |
|---|---|---|---|---|
| hex socket | s across flats: M3 2, M4 2.5, M5 3, M6 4, M8 5, M10 7, M12 8 mm; depth t: 1.5, 2.3, 2.7, 3, 3.8, 4.5, 5 mm | hex key of the same size | socket | din-7984-* |
| shank (thread as plain cylinder) | Ø3, 4, 5, 6, 8, 10, 12 mm (thread major) | tapped hole of the thread, or a clearance hole (see socket-head-cap-screws-metric for clearance values) | designed | din-7984-* |
| head | Ø dk max × k max: M3 5.5 × 2, M4 7 × 2.8, M5 8.5 × 3.5, M6 10 × 4, M8 13 × 5, M10 16 × 6, M12 18 × 7 mm | counterbore at least this wide and deep (the standards read give no counterbore size) | designed | din-7984-* |

## Sizes

| standard / source | size | P (mm) | b min (L ≤ 125) | head dia dk (max / min) | head height k (max / min) | socket s (AF) | socket depth t | other columns as printed |
|---|---|---|---|---|---|---|---|---|
| DIN 7984 (Westfield) | M3 | 0.5 | 12 | 5.5 / 5.32 | 2.0 / 1.86 | 2 | 1.5 (1.38 – 1.62) | ds 3 / 2.86; dw min 4.84; e min 2.3; da max 3.6; r min 0.1; lf max 0.51; v max 0.3 |
| DIN 7984 (Westfield) | M4 | 0.7 | 14 | 7 / 6.78 | 2.8 / 2.66 | 2.5 | 2.3 (2.18 – 2.42) | ds 4 / 3.82; dw min 6.2; e min 2.87; da max 4.7; r min 0.2; lf max 0.6; v max 0.4 |
| DIN 7984 (Westfield) | M5 | 0.8 | 16 | 8.5 / 8.28 | 3.5 / 3.32 | 3 | 2.7 (2.58 – 2.82) | ds 5 / 4.82; dw min 7.7; e min 3.44; da max 5.7; r min 0.2; lf max 0.6; v max 0.5 |
| DIN 7984 (Westfield) | M6 | 1 | 18 | 10 / 9.78 | 4.0 / 3.82 | 4 | 3 (2.88 – 3.12) | ds 6 / 5.82; dw min 9.2; e min 4.58; da max 6.8; r min 0.25; lf max 0.68; v max 0.6 |
| DIN 7984 (Westfield) | M8 | 1.25 | 22 | 13 / 12.73 | 5.0 / 4.82 | 5 | 3.8 (3.65 – 3.95) | ds 8 / 7.78; dw min 12.03; e min 5.72; da max 9.2; r min 0.4; lf max 1.02; v max 0.8 |
| DIN 7984 (Westfield) | M10 | 1.5 | 26 | 16 / 15.73 | 6.0 / 5.82 | 7 | 4.5 (4.35 – 4.65) | ds 10 / 9.78; dw min 15.03; e min 8.01; da max 11.2; r min 0.4; lf max 1.02; v max 1.0 |
| DIN 7984 (Westfield) | M12 | 1.75 | 30 | 18 / 17.73 | 7 / 6.78 | 8 | 5 (4.85 – 5.15) | ds 12 / 11.73; dw min 17.03; e min 9.15; da max 13.7; r min 0.6; lf max 1.87; v max 1.2 |
| DIN 7984 (Westfield) | M14 | 2 | 34 | 21 / 20.67 | 8 / 7.78 | 10 | 5.3 (5.15 – 5.45) | ds 14 / 13.73; dw min 19.83; e min 11.43; da max 15.7; r min 0.6; lf max 1.87; v max 1.4 |
| DIN 7984 (Westfield) | M16 | 2 | 38 | 24 / 23.67 | 9 / 8.78 | 12 | 5.5 (5.35 – 5.65) | ds 16 / 15.73; dw min 22.83; e min 13.72; da max 17.7; r min 0.6; lf max 1.87; v max 1.6 |
| DIN 7984 (Westfield) | M18 | 2.5 | 42 | 27 / 26.67 | 10 / 9.78 | 12 | 6.5 (6.32 – 6.68) | ds 18 / 17.73; dw min 25.83; e min 13.72; da max 20.2; r min 0.6; lf max 1.87; v max 1.8 |
| DIN 7984 (Westfield) | M20 | 2.5 | 46 | 30 / 29.67 | 11 / 10.73 | 14 | 7.5 (7.32 – 7.68) | ds 20 / 19.67; dw min 28.83; e min 16; da max 22.4; r min 0.8; lf max 2.04; v max 2.0 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M4 | 0.7 | 14; >125: —; >200: — | 7 (max) | 2.8 (max) | 3 | t1 1.6; t2 min 3.3 | e min 3.44; dh min 2 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M5 | 0.8 | 16; >125: —; >200: — | 8.5 (max) | 3.5 (max) | 4 | t1 2; t2 min 4 | e min 4.58; dh min 2.5 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M6 | 1 | 18; >125: —; >200: — | 10 (max) | 4 (max) | 5 | t1 2.5; t2 min 5 | e min 5.72; dh min 3 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M8 | 1.25 | 22; >125: —; >200: — | 13 (max) | 5 (max) | 6 | t1 3; t2 min 6.5 | e min 6.86; dh min 4 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M10 | 1.5 | 26; >125: 32; >200: — | 16 (max) | 6.5 (max) | 8 | t1 3.5; t2 min 7.5 | e min 9.15; dh min 5 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M12 | 1.75 | 30; >125: 36; >200: — | 18 (max) | 7.5 (max) | 10 | t1 4; t2 min 9 | e min 11.43; dh min 6 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M14 | 2 | 34; >125: 40; >200: — | 21 (max) | 8.5 (max) | 12 | t1 4.5; t2 min 10 | e min 13.72; dh min 7 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M16 | 2 | 38; >125: 44; >200: 57 | 24 (max) | 10 (max) | 14 | t1 5.5; t2 min 11.5 | e min 16; dh min 8 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M18 | 2.5 | 42; >125: 48; >200: 61 | 27 (max) | 11 (max) | 14 | t1 6; t2 min 12.5 | e min 16; dh min 8 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M20 | 2.5 | 46; >125: 52; >200: 65 | 30 (max) | 12 (max) | 17 | t1 6.5; t2 min 14 | e min 19.44; dh min 10 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M22 | 2.5 | 50; >125: 56; >200: 69 | 33 (max) | 13 (max) | 17 | t1 7; t2 min 15 | e min 19.44; dh min 10 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M24 | 3 | 54; >125: 60; >200: 73 | 36 (max) | 14 (max) | 19 | t1 7; t2 min 16 | e min 21.73; dh min 12 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M27 | 3 | 60; >125: 66; >200: 79 | 40 (max) | 16 (max) | 19 | t1 8.5; t2 min 17 | e min 21.73; dh min 12 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M30 | 3.5 | 66; >125: 72; >200: 85 | 45 (max) | 17.5 (max) | 22 | t1 9; t2 min 19 | e min 25.15; dh min 15 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M33 | 3.5 | 72; >125: 78; >200: 91 | 50 (max) | 19.5 (max) | 24 | t1 10; t2 min 20 | e min 27.43; dh min 16.5 |
| DIN 6912 pilot recess (fasten.it 03-2021) | M36 | 4 | 78; >125: 84; >200: 97 | 54 (max) | 21.5 (max) | 27 | t1 11.5; t2 min 24 | e min 30.85; dh min 18 |

## Where the files are

- Westfield Fasteners: [DIN 7984 hexagon socket cap screws with low head, M3 to M20: P, b, da, dk, ds, dw, e, k, lf, r, s, t, v (max / min)](https://westfieldfasteners.co.uk/Standards/ScrewBolt-SHCapLow-M.html) — web — Distributor reference; numbers only
- Ferrofast (DIN fasteners): [DIN 7984 low head socket head cap screws: thread length b1, head diameter d2, head height k, key size s, key engagement t (min / max), M3 to M24](https://din-fasteners.ferrobend.com/screws/din-7984) — web — Distributor reference; numbers only. Contains visible data errors (M10 k max / k min, M18 s)
- fasten.it: [DIN 6912 Low head socket cap screws with pilot recess (03-2021, supersedes 06-2009): d, P, b, dk max, k max, s nom, e min, dh min, t1 nom, t2 min, M4 to M36](https://fasten.it/norms/norm/din_6912) — web — Reference page; numbers only
- Aspen Fasteners: [Metric DIN 6912 spec: P, b, dk, da, dh, ds, dw, e, lf, k, r, s, t1, t2, v, M4 to M36 (page notes that it was compiled from public sources and may contain errors)](https://www.aspenfasteners.com/content/pdf/Metric_DIN_6912_spec.pdf) — web — Distributor data sheet; numbers only
- McMaster-Carr: [DIN 6912 pilot-recess socket screws (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/screws/specifications-met~din-6912) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)
- McMaster-Carr: [Pilot-recess screws (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/pilot-recess-screws) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)

## Free STEP/STL (7 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/index.json

- din-7984-m3-low-head-screw-envelope: [STEP](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m3-low-head-screw-envelope.step) · [STL](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m3-low-head-screw-envelope.stl) — DIN 7984 M3 low-head socket cap screw envelope: head Ø5.5 × 2.0 mm (dk max, k max), 2 mm hex socket 1.5 mm deep (t nominal, flat bottom), plain shank Ø3 × 12 mm under the head (example length, Xem's choice; no thread, no head edge radius, no chamfer)
- din-7984-m4-low-head-screw-envelope: [STEP](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m4-low-head-screw-envelope.step) · [STL](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m4-low-head-screw-envelope.stl) — DIN 7984 M4 low-head socket cap screw envelope: head Ø7 × 2.8 mm (dk max, k max), 2.5 mm hex socket 2.3 mm deep (t nominal, flat bottom), plain shank Ø4 × 16 mm under the head (example length, Xem's choice; no thread, no head edge radius, no chamfer)
- din-7984-m5-low-head-screw-envelope: [STEP](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m5-low-head-screw-envelope.step) · [STL](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m5-low-head-screw-envelope.stl) — DIN 7984 M5 low-head socket cap screw envelope: head Ø8.5 × 3.5 mm (dk max, k max), 3 mm hex socket 2.7 mm deep (t nominal, flat bottom), plain shank Ø5 × 20 mm under the head (example length, Xem's choice; no thread, no head edge radius, no chamfer)
- din-7984-m6-low-head-screw-envelope: [STEP](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m6-low-head-screw-envelope.step) · [STL](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m6-low-head-screw-envelope.stl) — DIN 7984 M6 low-head socket cap screw envelope: head Ø10 × 4.0 mm (dk max, k max), 4 mm hex socket 3 mm deep (t nominal, flat bottom), plain shank Ø6 × 24 mm under the head (example length, Xem's choice; no thread, no head edge radius, no chamfer)
- din-7984-m8-low-head-screw-envelope: [STEP](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m8-low-head-screw-envelope.step) · [STL](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m8-low-head-screw-envelope.stl) — DIN 7984 M8 low-head socket cap screw envelope: head Ø13 × 5.0 mm (dk max, k max), 5 mm hex socket 3.8 mm deep (t nominal, flat bottom), plain shank Ø8 × 32 mm under the head (example length, Xem's choice; no thread, no head edge radius, no chamfer)
- din-7984-m10-low-head-screw-envelope: [STEP](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m10-low-head-screw-envelope.step) · [STL](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m10-low-head-screw-envelope.stl) — DIN 7984 M10 low-head socket cap screw envelope: head Ø16 × 6.0 mm (dk max, k max), 7 mm hex socket 4.5 mm deep (t nominal, flat bottom), plain shank Ø10 × 40 mm under the head (example length, Xem's choice; no thread, no head edge radius, no chamfer)
- din-7984-m12-low-head-screw-envelope: [STEP](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m12-low-head-screw-envelope.step) · [STL](https://xemstudio.com/files/hardware/low-head-socket-cap-screws-din-7984-6912/din-7984-m12-low-head-screw-envelope.stl) — DIN 7984 M12 low-head socket cap screw envelope: head Ø18 × 7 mm (dk max, k max), 8 mm hex socket 5 mm deep (t nominal, flat bottom), plain shank Ø12 × 48 mm under the head (example length, Xem's choice; no thread, no head edge radius, no chamfer)

## Questions

**What is the head height of an M6 DIN 7984 screw?**

4.0 mm max and 3.82 mm min, head diameter 10 mm max (9.78 min), with a 4 mm hex socket 3 mm deep (Westfield).

**What hex key fits an M8 low-head socket screw?**

5 mm for DIN 7984 (head 13 mm × 5 mm); 6 mm for DIN 6912 (head 13 × 5 mm).

**What is DIN 6912?**

A low-head socket cap screw with a pilot recess (guide hole) in the head, M4 to M36; head dimensions equal DIN 7984's for M4 to M8 but the sockets differ (s 3, 4, 5, 6 against 2.5, 3, 4, 5 mm).

## 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, M10 to M24 (ISO 4762 / DIN 912)](https://xemstudio.com/objects/socket-head-cap-screws-metric-m10-m24/)
- [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/)
- [Hexalobular (Torx) socket screws: ISO 14579 cap, ISO 14580 low cheese and ISO 14583 pan head, M2–M20: head diameter, height, socket number, depth + head envelopes](https://xemstudio.com/objects/hexalobular-socket-screws-iso-14579-14580-14583/)
- [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](https://xemstudio.com/objects/hex-keys-iso-2936-asme-b18-3/)
- [Hex nuts, M2–M8 (ISO 4032)](https://xemstudio.com/objects/hex-nuts-metric/)
- [Metric machine screws M1.6–M10: pan head ISO 7045 (cross) / ISO 1580 (slotted), cheese head ISO 1207, countersunk ISO 7046-1 — head sizes, recess sizes + models](https://xemstudio.com/objects/machine-screws-metric-pan-cheese-csk/)