DIN 7991 – Hexagon socket countersunk head screws
Dimensions, materials and applications – with the ISO counterpart ISO 10642.
DIN 7991 covers hexagon socket countersunk head screws: a 90° countersunk head with an internal hexagon drive, in metric coarse thread. The head sits flush with the surface, which makes DIN 7991 the choice for covers, guides, slides and any surface that has to stay smooth.
The ISO counterpart is ISO 10642, but the two are not fully interchangeable. ISO 10642 has a different head diameter and head height, so a screw to one standard does not always sit flush in a countersink made for the other. ISO 10642 also leaves out M18, M22 and M24 and does not cover stainless steel. When replacing one with the other, check the countersink on the drawing first.
We supply DIN 7991 screws from M3 to M24 in steel 8.8, 10.9 and 12.9 and in stainless A2-70, A4-70 and A4-80. Stainless sizes up to M12 are also available EPK-treated for cleanroom equipment. Every delivery comes with an EN 10204 3.1 certificate; 3.2 on request.
Applications
- Flush-mounted covers, guards and panels
- Linear guides, slides and wear plates
- Cleanroom and vacuum equipment in A2 or A4 with EPK treatment
- Tooling and fixtures with smooth clamping faces
Nederlands: verzonken inbusbouten DIN 7991, verzonkenkopschroeven met binnenzeskant, RVS verzonken inbus A2 / A4.
Main dimensions in mm.
The full table with all sizes and lengths is in the datasheet.
| Thread d | M3 | M4 | M5 | M6 | M8 | M10 | M12 | M14 | M16 | M18 | M20 | M22 | M24 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| P | – | 0.5 | 0.7 | 0.8 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | 2.5 | 2.5 | 2.5 | 3 |
| b | l ≤ 125 | 12.00 | 14.00 | 16.00 | 18.00 | 22.00 | 26.00 | 30.00 | 34.00 | 38.00 | 42.00 | 46.00 | 50.00 | 54.00 |
| 125 < l ≤ 200 | – | – | – | 24.00 | 28.00 | 32.00 | 36.00 | 40.00 | 44.00 | 48.00 | 52.00 | 56.00 | 60.00 | |
| l > 200 | – | – | – | – | – | 45.00 | 49.00 | 53.00 | 57.00 | 61.00 | 65.00 | 69.00 | 73.00 | |
| c | – | 0.20 | 0.30 | 0.30 | 0.30 | 0.40 | 0.50 | 0.50 | 0.50 | 0.50 | 0.50 | 0.50 | 1.00 | 1.00 |
| dk | nominal | 6.00 | 8.00 | 10.00 | 12.00 | 16.00 | 20.00 | 24.00 | 27.00 | 30.00 | 33.00 | 36.00 | 36.00 | 39.00 |
| min. | 5.70 | 7.64 | 9.64 | 11.57 | 15.57 | 19.48 | 23.48 | 26.48 | 29.48 | 32.38 | 35.38 | 35.38 | 38.38 | |
| da | max. | 3.60 | 4.70 | 5.70 | 6.80 | 9.20 | 11.20 | 13.70 | 15.70 | 17.70 | 20.20 | 22.40 | 24.40 | 26.40 |
| ds | nominal = max. | 3.00 | 4.00 | 5.00 | 6.00 | 8.00 | 10.00 | 12.00 | 14.00 | 16.00 | 18.00 | 20.00 | 22.00 | 24.00 |
| min. | 2.86 | 3.82 | 4.82 | 5.82 | 7.78 | 9.78 | 11.73 | 13.73 | 15.73 | 17.73 | 19.67 | 21.67 | 23.67 | |
| e | min. | 2.30 | 2.87 | 3.44 | 4.58 | 5.72 | 6.86 | 9.15 | 11.43 | 11.43 | 13.72 | 13.72 | 16.00 | 16.00 |
| k | max. | 1.70 | 2.30 | 2.80 | 3.30 | 4.40 | 5.50 | 6.50 | 7.00 | 7.50 | 8.00 | 8.50 | 13.10 | 14.00 |
| r | min. | 0.10 | 0.20 | 0.20 | 0.30 | 0.50 | 0.50 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.60 |
| s | nominal | 2.00 | 2.50 | 3.00 | 4.00 | 5.00 | 6.00 | 8.00 | 10.00 | 10.00 | 12.00 | 12.00 | 14.00 | 14.00 |
| max. | 2.10 | 2.60 | 3.10 | 4.12 | 5.14 | 6.14 | 8.17 | 10.17 | 10.17 | 12.21 | 12.21 | 14.21 | 14.21 | |
| min. | 2.02 | 2.52 | 3.02 | 4.02 | 5.02 | 6.02 | 8.03 | 10.03 | 10.03 | 12.03 | 12.03 | 14.03 | 14.03 | |
| t | nominal = max. | 1.20 | 1.80 | 2.30 | 2.50 | 3.50 | 4.40 | 4.60 | 4.80 | 5.30 | 5.50 | 5.90 | 8.80 | 10.30 |
| min. | 0.95 | 1.50 | 2.05 | 2.25 | 3.20 | 4.10 | 4.30 | 4.50 | 5.00 | 5.20 | 5.60 | 8.44 | 9.87 | |
Show all 3 tables ↓Show fewer tables ↑
| Length l | M3 | M4 | M5 | M6 | M8 | M10 | M12 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| nom. | min. | max. | ls | lg | ls | lg | ls | lg | ls | lg | ls | lg | ls | lg | ls | lg |
| 8 | 7.71 | 8.29 | – | 3.20 | – | 4.40 | – | 5.20 | – | 6.30 | – | – | – | – | – | – |
| 10 | 9.71 | 10.29 | – | 3.20 | – | 4.40 | – | 5.20 | – | 6.30 | – | 8.20 | – | – | – | – |
| 12 | 11.65 | 12.35 | – | 3.20 | – | 4.40 | – | 5.20 | – | 6.30 | – | 8.20 | – | 10.00 | – | – |
| 16 | 15.65 | 16.35 | – | 3.20 | – | 4.40 | – | 5.20 | – | 6.30 | – | 8.20 | – | 10.00 | – | – |
| 20 | 19.58 | 20.42 | – | 3.20 | – | 4.40 | – | 5.20 | – | 6.30 | – | 8.20 | – | 10.00 | – | 11.80 |
| 25 | 24.58 | 25.42 | 10.50 | 13.00 | – | 4.40 | – | 5.20 | – | 6.30 | – | 8.20 | – | 10.00 | – | 11.80 |
| 30 | 29.58 | 30.42 | 15.50 | 18.00 | 12.50 | 16.00 | – | 5.20 | – | 6.30 | – | 8.20 | – | 10.00 | – | 11.80 |
| 35 | 34.50 | 35.50 | – | – | 17.50 | 21.00 | 15.00 | 19.00 | – | 6.30 | – | 8.20 | – | 10.00 | – | 11.80 |
| 40 | 39.50 | 40.50 | – | – | 22.50 | 26.00 | 20.00 | 24.00 | 17.00 | 22.00 | – | 8.20 | – | 10.00 | – | 11.80 |
| 50 | 49.50 | 50.50 | – | – | – | – | 30.00 | 34.00 | 27.00 | 32.00 | 21.75 | 28.00 | 16.50 | 24.00 | – | 11.80 |
| 60 | 59.40 | 60.60 | – | – | – | – | – | – | – | – | 31.75 | 38.00 | 26.50 | 34.00 | 21.25 | 30.00 |
| 70 | 69.40 | 70.60 | – | – | – | – | – | – | – | – | – | – | 36.50 | 44.00 | 31.25 | 40.00 |
| Length l | M14 | M16 | M18 | M20 | M22 | M24 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| nom. | min. | max. | ls | lg | ls | lg | ls | lg | ls | lg | ls | lg | ls | lg |
| 25 | 24.58 | 25.42 | – | 13.00 | – | – | – | – | – | – | – | – | – | – |
| 30 | 29.58 | 30.42 | – | 13.00 | – | 13.50 | – | – | – | – | – | – | – | – |
| 35 | 34.50 | 35.50 | – | 13.00 | – | 13.50 | – | 15.50 | – | 16.00 | – | – | – | – |
| 40 | 39.50 | 40.50 | – | 13.00 | – | 13.50 | – | 15.50 | – | 16.00 | – | 20.60 | – | – |
| 50 | 49.50 | 50.50 | – | 13.00 | – | 13.50 | – | 15.50 | – | 16.00 | – | 20.60 | – | 23.00 |
| 60 | 59.40 | 60.60 | 16.00 | 26.00 | – | 13.50 | – | 15.50 | – | 16.00 | – | 20.60 | – | 23.00 |
| 70 | 69.40 | 70.60 | 26.00 | 36.00 | 22.00 | 32.00 | 15.50 | 28.00 | – | 16.00 | – | 20.60 | – | 23.00 |
| 80 | 79.40 | 80.60 | 36.00 | 46.00 | 32.00 | 42.00 | 25.50 | 38.00 | 21.50 | 34.00 | – | 20.60 | – | 23.00 |
| 90 | 89.30 | 90.70 | – | – | 42.00 | 52.00 | 35.50 | 48.00 | 31.50 | 44.00 | 27.50 | 40.00 | – | 23.00 |
| 100 | 99.30 | 100.70 | – | – | – | – | 45.50 | 58.00 | 41.50 | 54.00 | 37.50 | 50.00 | 31.00 | 46.00 |
- d
- Nominal thread diameter
- P
- Thread pitch, coarse
- b
- Thread length
- ds
- Screw shank diameter
- k
- Head height
- s
- Width across flats
- e
- Width across corners
- t
- Groove depth
- l
- Bolt length
- ls
- Shank to thread start length
Grades and finishes: hbsfasteners.nl/products/socket-screws.
Questions about DIN 7991.
- Can I replace DIN 7991 with ISO 10642?
- Not always. The head diameter and head height differ, so the screw may stand proud or sink too deep in an existing countersink. Check the countersink dimensions on your drawing, or send it to us and we will advise.
- Which property classes do you supply for DIN 7991?
- Steel in 8.8, 10.9 and 12.9, and stainless in A2-70, A4-70 and A4-80. Stainless screws up to M12 are also available EPK-treated for cleanroom use.
- What is DIN 7991?
- DIN 7991 is the standard for hexagon socket countersunk head screws (DIN 7991). HBS Solutions supplies DIN 7991 socket head cap screws from stock, with EN 10204 3.1 / 3.2 certificates.
- Which sizes does DIN 7991 cover?
- The HBS datasheet lists DIN 7991 from M3 to M24. The full dimension tables are on this page and in the free PDF datasheet.
- How do I order DIN 7991 socket head cap screws?
- Configure the part online or send your parts list through the quote form; HBS Solutions replies with a quotation within 24 hours. Stock items ship from 500.000+ pieces in stock in Almere, the Netherlands.
Often ordered together.
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