DIN 7991 vs ISO 10642
Hexagon Socket Countersunk Head Screw
Interchangeable except for the head diameter — 20 recorded dimensions differ. ISO 10642 replaced DIN 7991 as the current document.
M3 Head diameter6 → 6.72 mmM3 Head height1.7 → 1.86 mmM14 weightISO 10642 +17.0%DIN 7991 onlyM18, M22, M24ISO 10642 onlyM2, M2.5
We produce to whichever standard your drawing calls out, DIN 7991 included. ISO 10642 is the reference to specify on a new drawing.
What each number is
- DIN 7991Superseded by ISO 10642
- Hex Socket Countersunk Head ScrewEdition 1986-01 · 13 recorded sizes · M3 to M24
- ISO 10642Current
- Hexagon Socket Countersunk Head Screw12 recorded sizes · M2 to M20
Check your size
At M3 the two standards do not match.
| DIN 7991 | ISO 10642 | |
|---|---|---|
| dkHead Diameter (mm) | 6 | 6.72 |
| kNominal Head Height (mm) | 1.7 | 1.86 |
| kgper 1000 pcs at 30 mm | 1.47 | 1.53 |
| RFQwe produce to the standard you name |
Weight differenceISO 10642 is 3.9% heavier0.6 kg more steel at this quantity
We produce to whichever standard your order names.
Where they differ
20 recorded values across 10 diameters.
| Size | Dimension | DIN 7991 | ISO 10642 |
|---|---|---|---|
| M3 | dk · Head Diameter | 6 | 6.72 |
| M3 | k · Nominal Head Height | 1.7 | 1.86 |
| M4 | dk · Head Diameter | 8 | 8.96 |
| M4 | k · Nominal Head Height | 2.3 | 2.48 |
| M5 | dk · Head Diameter | 10 | 11.2 |
| M5 | k · Nominal Head Height | 2.8 | 3.1 |
| M6 | dk · Head Diameter | 12 | 13.44 |
| M6 | k · Nominal Head Height | 3.3 | 3.72 |
| M8 | dk · Head Diameter | 16 | 17.92 |
| M8 | k · Nominal Head Height | 4.4 | 4.96 |
| M10 | dk · Head Diameter | 20 | 22.4 |
| M10 | k · Nominal Head Height | 5.5 | 6.2 |
| M12 | dk · Head Diameter | 24 | 26.88 |
| M12 | k · Nominal Head Height | 6.5 | 7.44 |
| M14 | dk · Head Diameter | 27 | 30.8 |
| M14 | k · Nominal Head Height | 7 | 8.4 |
| M16 | dk · Head Diameter | 30 | 33.6 |
| M16 | k · Nominal Head Height | 7.5 | 8.8 |
| M20 | dk · Head Diameter | 36 | 40.32 |
| M20 | k · Nominal Head Height | 8.5 | 10.16 |
Differences on this page come from the TaurusFix confirmed dimension library, compared value by value and strictly against the standards themselves — not from a third-party equivalence chart.