Dimensions mm · values as the standard states them Size P k t A hexalobular d2 recess_no hexalobular ST2.9 ≤ 1.7
≤ 0.91
2.8
≤ 6.3
10
ST3.5 ≤ 2.35
≤ 1.3
3.35
≤ 8.2
15
ST4.2 ≤ 2.6
≤ 1.58
3.95
≤ 9.4
20
ST4.8 ≤ 2.8
≤ 1.78
4.5
≤ 10.4
25
ST5.5 ≤ 3
≤ 2.03
4.5
≤ 11.5
25
ST6.3 ≤ 3.15
≤ 2.42
5.6
≤ 12.6
30
Ranges read min – max; ≤ / ≥ where the standard gives one limit, ≈ for approximate values. Sizes in (brackets) are non-preferred. Select a row for its size sheet.
Size sheet · ISO 14586
ST2.9
k head height ≤ 1.7
t groove depth ≤ 0.91
A groove (hexalobular) 2.8
d2 head diameter ≤ 6.3
recess_no drive size (hexalobular) 10 Size sheet · ISO 14586
ST3.5
k head height ≤ 2.35
t groove depth ≤ 1.3
A groove (hexalobular) 3.35
d2 head diameter ≤ 8.2
recess_no drive size (hexalobular) 15 Size sheet · ISO 14586
ST4.2
k head height ≤ 2.6
t groove depth ≤ 1.58
A groove (hexalobular) 3.95
d2 head diameter ≤ 9.4
recess_no drive size (hexalobular) 20 Size sheet · ISO 14586
ST4.8
k head height ≤ 2.8
t groove depth ≤ 1.78
A groove (hexalobular) 4.5
d2 head diameter ≤ 10.4
recess_no drive size (hexalobular) 25 Size sheet · ISO 14586
ST5.5
k head height ≤ 3
t groove depth ≤ 2.03
A groove (hexalobular) 4.5
d2 head diameter ≤ 11.5
recess_no drive size (hexalobular) 25 Size sheet · ISO 14586
ST6.3
k head height ≤ 3.15
t groove depth ≤ 2.42
A groove (hexalobular) 5.6
d2 head diameter ≤ 12.6
recess_no drive size (hexalobular) 30 Provenance
Reviewed — dimensions cross-checked against the official ISO preview; values match.
Accessed 2026-09-23 · For design and safety-critical use, consult the current edition of the standard.
Data notes (1) Dimensions cross-checked against the official ISO 14586:2011 preview — values match.