Dimensions mm · values as the standard states them Type C Type F
Size P dk k da a r t n rf w y y ST2.2 3.7 – 4
1.1 – 1.3
≤ 2.8
≤ 0.8
≥ 0.1
≥ 0.5
0.5
0.56 – 0.7
≈ 0.6
≥ 0.5
2
1.6
ST2.9 5.3 – 5.6
1.6 – 1.8
≤ 3.5
≤ 1.1
≥ 0.1
≥ 0.7
0.8
0.86 – 1
≈ 0.8
≥ 0.7
2.6
2.1
ST3.5 6.6 – 7
1.9 – 2.1
≤ 4.1
≤ 1.3
≥ 0.1
≥ 0.8
1
1.06 – 1.2
≈ 1
≥ 0.8
3.2
2.5
ST4.2 7.6 – 8
2.2 – 2.4
≤ 4.9
≤ 1.4
≥ 0.2
≥ 1
1.2
1.26 – 1.51
≈ 1.2
≥ 0.9
3.7
2.8
ST4.8 9.1 – 9.5
2.7 – 3
≤ 5.5
≤ 1.6
≥ 0.2
≥ 1.2
1.2
1.26 – 1.51
≈ 1.5
≥ 1.2
4.3
3.2
ST5.5 10.6 – 11
2.9 – 3.2
≤ 6.3
≤ 1.8
≥ 0.25
≥ 1.3
1.6
1.66 – 1.91
≈ 1.6
≥ 1.3
5
3.6
ST6.3 11.6 – 12
3.3 – 3.6
≤ 7.1
≤ 1.8
≥ 0.25
≥ 1.4
1.6
1.66 – 1.91
≈ 1.8
≥ 1.4
6
3.6
ST8 15.6 – 16
4.5 – 4.8
≤ 9.2
≤ 2.1
≥ 0.4
≥ 1.9
2
2.06 – 2.31
≈ 2.4
≥ 1.9
7.5
4.2
ST9.5 19.5 – 20
5.7 – 6
≤ 10.7
≤ 2.1
≥ 0.4
≥ 2.4
2.5
2.56 – 2.81
≈ 3
≥ 2.4
8
4.2
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.
Length tolerances 4.5 3.7 – 5.3
6.5 5.7 – 7.3
9.5 8.7 – 10.3
13 12.2 – 13.8
16 15.2 – 16.8
19 18.2 – 19.8
22 21.2 – 22.8
25 24.2 – 25.8
32 30.7 – 33.3
38 36.7 – 39.3
45 43.7 – 46.3
50 48.7 – 51.3
Size sheet · ISO 1481
ST2.2
dk head diameter 3.7 – 4
k head height 1.1 – 1.3
da transition diameter ≤ 2.8
a ≤ 0.8
r fillet radius ≥ 0.1
t groove depth ≥ 0.5
n groove width 0.5
rf ≈ 0.6
w ≥ 0.5
y 2
y 1.6 Standard lengths
4.5 · 6.5 · 9.5 · 13 · 16
Size sheet · ISO 1481
ST2.9
dk head diameter 5.3 – 5.6
k head height 1.6 – 1.8
da transition diameter ≤ 3.5
a ≤ 1.1
r fillet radius ≥ 0.1
t groove depth ≥ 0.7
n groove width 0.8
rf ≈ 0.8
w ≥ 0.7
y 2.6
y 2.1 Standard lengths
6.5 · 9.5 · 13 · 16 · 19
Size sheet · ISO 1481
ST3.5
dk head diameter 6.6 – 7
k head height 1.9 – 2.1
da transition diameter ≤ 4.1
a ≤ 1.3
r fillet radius ≥ 0.1
t groove depth ≥ 0.8
n groove width 1
rf ≈ 1
w ≥ 0.8
y 3.2
y 2.5 Standard lengths
6.5 · 9.5 · 13 · 16 · 19 · 22
Size sheet · ISO 1481
ST4.2
dk head diameter 7.6 – 8
k head height 2.2 – 2.4
da transition diameter ≤ 4.9
a ≤ 1.4
r fillet radius ≥ 0.2
t groove depth ≥ 1
n groove width 1.2
rf ≈ 1.2
w ≥ 0.9
y 3.7
y 2.8 Standard lengths
9.5 · 13 · 16 · 19 · 22 · 25
Size sheet · ISO 1481
ST4.8
dk head diameter 9.1 – 9.5
k head height 2.7 – 3
da transition diameter ≤ 5.5
a ≤ 1.6
r fillet radius ≥ 0.2
t groove depth ≥ 1.2
n groove width 1.2
rf ≈ 1.5
w ≥ 1.2
y 4.3
y 3.2 Standard lengths
9.5 · 13 · 16 · 19 · 22 · 25 · 32
Size sheet · ISO 1481
ST5.5
dk head diameter 10.6 – 11
k head height 2.9 – 3.2
da transition diameter ≤ 6.3
a ≤ 1.8
r fillet radius ≥ 0.25
t groove depth ≥ 1.3
n groove width 1.6
rf ≈ 1.6
w ≥ 1.3
y 5
y 3.6 Standard lengths
13 · 16 · 19 · 22 · 25 · 32
Size sheet · ISO 1481
ST6.3
dk head diameter 11.6 – 12
k head height 3.3 – 3.6
da transition diameter ≤ 7.1
a ≤ 1.8
r fillet radius ≥ 0.25
t groove depth ≥ 1.4
n groove width 1.6
rf ≈ 1.8
w ≥ 1.4
y 6
y 3.6 Standard lengths
13 · 16 · 19 · 22 · 25 · 32 · 38
Size sheet · ISO 1481
ST8
dk head diameter 15.6 – 16
k head height 4.5 – 4.8
da transition diameter ≤ 9.2
a ≤ 2.1
r fillet radius ≥ 0.4
t groove depth ≥ 1.9
n groove width 2
rf ≈ 2.4
w ≥ 1.9
y 7.5
y 4.2 Standard lengths
16 · 19 · 22 · 25 · 32 · 38 · 45 · 50
Size sheet · ISO 1481
ST9.5
dk head diameter 19.5 – 20
k head height 5.7 – 6
da transition diameter ≤ 10.7
a ≤ 2.1
r fillet radius ≥ 0.4
t groove depth ≥ 2.4
n groove width 2.5
rf ≈ 3
w ≥ 2.4
y 8
y 4.2 Standard lengths
16 · 19 · 22 · 25 · 32 · 38 · 45 · 50
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 (2) Dimensions cross-checked against the official ISO 1481:2011 preview — values match. The source publishes one identical table for DIN 7971, ISO 1481.