Dimensions mm · values as the standard states them Form A Form B
Size P s e k r a1 dp l l z2 z5 M6 1 8
8.79
5
0.25
3
4
12 – 60
12 – 40
3
1.75
M8 1.25 10
11.05
6
0.4
3.75
5.5
16 – 60
16 – 60
4
2.5
M10 1.5 13
14.38
7
0.4
4.5
7
20 – 60
20 – 60
5
3
M12 1.75 16
17.77
9
0.6
5.25
8.5
25 – 120
25 – 100
6
3.5
M16 2 18
19.92
11
0.6
6
12
30 – 120
30 – 120
8
4.5
M20 2.5 24
26.75
14
0.8
7.5
15
40 – 120
40 – 120
10
5
M24 3 30
33.53
17
0.8
9
18
45 – 120
45 – 120
12
6
M30 3.5 36
39.98
21
1
10.5
23
60 – 120
60 – 120
15
8
M36 4 46
51.28
25
1
12
28
80 – 200
80 – 200
18
10
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 · DIN 564 B
M6
s width across flats 8
e width across corners 8.79
k head height 5
r fillet radius 0.25
a1 length undercut 3
dp diameter of the ejector 4
l length of bolt 12 – 60
l length of bolt 12 – 40
z2 length of the ejector 3
z5 height of the cone 1.75 Thread · ISO 261/262
Pitch P 1
d2 5.35
d3 4.773
Tap drill 5
Stress area As 20.12 mm² Size sheet · DIN 564 B
M8
s width across flats 10
e width across corners 11.05
k head height 6
r fillet radius 0.4
a1 length undercut 3.75
dp diameter of the ejector 5.5
l length of bolt 16 – 60
l length of bolt 16 – 60
z2 length of the ejector 4
z5 height of the cone 2.5 Thread · ISO 261/262
Pitch P 1.25
d2 7.188
d3 6.466
Tap drill 6.75
Stress area As 36.61 mm² Size sheet · DIN 564 B
M10
s width across flats 13
e width across corners 14.38
k head height 7
r fillet radius 0.4
a1 length undercut 4.5
dp diameter of the ejector 7
l length of bolt 20 – 60
l length of bolt 20 – 60
z2 length of the ejector 5
z5 height of the cone 3 Thread · ISO 261/262
Pitch P 1.5
d2 9.026
d3 8.16
Tap drill 8.5
Stress area As 57.99 mm² Size sheet · DIN 564 B
M12
s width across flats 16
e width across corners 17.77
k head height 9
r fillet radius 0.6
a1 length undercut 5.25
dp diameter of the ejector 8.5
l length of bolt 25 – 120
l length of bolt 25 – 100
z2 length of the ejector 6
z5 height of the cone 3.5 Thread · ISO 261/262
Pitch P 1.75
d2 10.863
d3 9.853
Tap drill 10.25
Stress area As 84.27 mm² Size sheet · DIN 564 B
M16
s width across flats 18
e width across corners 19.92
k head height 11
r fillet radius 0.6
a1 length undercut 6
dp diameter of the ejector 12
l length of bolt 30 – 120
l length of bolt 30 – 120
z2 length of the ejector 8
z5 height of the cone 4.5 Thread · ISO 261/262
Pitch P 2
d2 14.701
d3 13.546
Tap drill 14
Stress area As 156.67 mm² Size sheet · DIN 564 B
M20
s width across flats 24
e width across corners 26.75
k head height 14
r fillet radius 0.8
a1 length undercut 7.5
dp diameter of the ejector 15
l length of bolt 40 – 120
l length of bolt 40 – 120
z2 length of the ejector 10
z5 height of the cone 5 Thread · ISO 261/262
Pitch P 2.5
d2 18.376
d3 16.933
Tap drill 17.5
Stress area As 244.79 mm² Size sheet · DIN 564 B
M24
s width across flats 30
e width across corners 33.53
k head height 17
r fillet radius 0.8
a1 length undercut 9
dp diameter of the ejector 18
l length of bolt 45 – 120
l length of bolt 45 – 120
z2 length of the ejector 12
z5 height of the cone 6 Thread · ISO 261/262
Pitch P 3
d2 22.051
d3 20.319
Tap drill 21
Stress area As 352.5 mm² Size sheet · DIN 564 B
M30
s width across flats 36
e width across corners 39.98
k head height 21
r fillet radius 1
a1 length undercut 10.5
dp diameter of the ejector 23
l length of bolt 60 – 120
l length of bolt 60 – 120
z2 length of the ejector 15
z5 height of the cone 8 Thread · ISO 261/262
Pitch P 3.5
d2 27.727
d3 25.706
Tap drill 26.5
Stress area As 560.59 mm² Size sheet · DIN 564 B
M36
s width across flats 46
e width across corners 51.28
k head height 25
r fillet radius 1
a1 length undercut 12
dp diameter of the ejector 28
l length of bolt 80 – 200
l length of bolt 80 – 200
z2 length of the ejector 18
z5 height of the cone 10 Thread · ISO 261/262
Pitch P 4
d2 33.402
d3 31.093
Tap drill 32
Stress area As 816.72 mm² Provenance
Draft — values taken from a single source and not yet cross-checked.
fasteners.eu dimensions, lengths, materials, property classes, current norm, equivalent norms Accessed 2026-09-23 · For design and safety-critical use, consult the current edition of the standard.