Dimensions mm · values as the standard states them Size P k t A hexalobular d2 recess_no hexalobular ST2.9 ≤ 2.4
≤ 1.27
2.8
≤ 5.6
10
ST3.5 ≤ 2.6
≤ 1.4
3.35
≤ 7
15
ST4.2 ≤ 3.1
≤ 1.8
3.95
≤ 8
20
ST4.8 ≤ 3.7
≤ 2.03
4.5
≤ 9.5
25
ST5.5 ≤ 4
≤ 2.03
4.5
≤ 11
25
ST6.3 ≤ 4.6
≤ 2.42
5.6
≤ 12
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 14585
ST2.9
k head height ≤ 2.4
t groove depth ≤ 1.27
A groove (hexalobular) 2.8
d2 head diameter ≤ 5.6
recess_no drive size (hexalobular) 10 Size sheet · ISO 14585
ST3.5
k head height ≤ 2.6
t groove depth ≤ 1.4
A groove (hexalobular) 3.35
d2 head diameter ≤ 7
recess_no drive size (hexalobular) 15 Size sheet · ISO 14585
ST4.2
k head height ≤ 3.1
t groove depth ≤ 1.8
A groove (hexalobular) 3.95
d2 head diameter ≤ 8
recess_no drive size (hexalobular) 20 Size sheet · ISO 14585
ST4.8
k head height ≤ 3.7
t groove depth ≤ 2.03
A groove (hexalobular) 4.5
d2 head diameter ≤ 9.5
recess_no drive size (hexalobular) 25 Size sheet · ISO 14585
ST5.5
k head height ≤ 4
t groove depth ≤ 2.03
A groove (hexalobular) 4.5
d2 head diameter ≤ 11
recess_no drive size (hexalobular) 25 Size sheet · ISO 14585
ST6.3
k head height ≤ 4.6
t groove depth ≤ 2.42
A groove (hexalobular) 5.6
d2 head diameter ≤ 12
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 14585:2011 preview — values match.