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Metric Socket Head Cap Screws Size Table

Engineering ANSI Hardware Design Data
Engineering Metric Hardware Design Data

All dimensions are in millimeters.

Drilled head metric hexagon socket head cap screws normally are not available in screw sizes smaller than M3 nor larger than M36. The M3 and M4 nominal screw sizes have two drilled holes spaced 180 degrees apart. Nominal screw sizes M5 and larger have six drilled holes spaced 60 degrees apart unless the purchaser specifies two drilled holes. The positioning of holes on opposite sides of the socket should be such that the hole alignment check plug will pass completely through the head without any deflection. When so specified by the purchaser, the edges of holes on the outside surface of the head will be chamfered 45 degrees to a depth of 0.30 to 0.50 mm.

Socket Head Cap Screws & Metric Series

American National Standard Socket Head Cap Screws & Metric Series per. ANSI/ASME B18.3.1M

 

Nom.
Size
Thread
Pitch
Body
Diameter
D
Head
Diameter
A
Head
Height
H
Chamfer
or
Radius
S
Hexagon
Socket
Size
J
Spline
Socket
Sizea
M
Key
Engagement
T
Transition
Dia.
B
Max
Min
Max
Min
Max
Min
Max
Nom.
Nom.
Min
Max
M1.6 × 0.35
1.60
1.46
3.00
2.87
1.60
1.52
0.16
1.5
1.829
0.80
2.0
M2 × 0.4
2.00
1.86
3.80
3.65
2.00
1.91
0.20
1.5
1.829
1.00
2.6
M2.5 × 0.45
2.50
2.36
4.50
4.33
2.50
2.40
0.25
2.0
2.438
1.25
3.1
M3 × 0.5
3.00
2.86
5.50
5.32
3.00
2.89
0.30
2.5
2.819
1.50
3.6
M4 × 0.7
4.00
3.82
7.00
6.80
4.00
3.88
0.40
3.0
3.378
2.00
4.7
M5 × 0.8
5.00
4.82
8.50
8.27
5.00
4.86
0.50
4.0
4.648
2.50
5.7
M6 × 1
6.00
5.82
10.00
9.74
6.00
5.85
0.60
5.0
5.486
3.00
6.8
M8 × 1.25
8.00
7.78
13.00
12.70
8.00
7.83
0.80
6.0
7.391
4.00
9.2
M10 × 1.5
10.00
9.78
16.00
15.67
10.00
9.81
1.00
8.0
5.00
11.2
M12 × 1.75
12.00
11.73
18.00
17.63
12.00
11.79
1.20
10.0
6.00
14.2
M14 × 2b
14.00
13.73
21.00
20.60
14.00
13.77
1.40
12.0
7.00
16.2
M16 × 2
16.00
15.73
24.00
23.58
16.00
15.76
1.60
14.0
8.00
18.2
M20 × 2.5
20.00
19.67
30.00
29.53
20.00
19.73
2.00
17.0
10.00
22.4
M24 × 3
24.00
23.67
36.00
35.48
24.00
23.70
2.40
19.0
12.00
26.4
M30 × 3.5
30.00
29.67
45.00
44.42
30.00
29.67
3.00
22.0
15.00
33.4
M36 × 4
36.00
35.61
54.00
53.37
36.00
35.64
3.60
27.0
18.00
39.4
M42 × 4.5
42.00
41.61
63.00
62.31
42.00
41.61
4.20
32.0
21.00
45.6
M48 × 5
48.00
47.61
72.00
71.27
48.00
47.58
4.80
36.0
24.00
52.6