材质 
M12
1.75
13.7
13.4
28
2.5
8
7.5
20
22
21.5
M16
2
17.7
17.4
36
2.5
10
9.5
24
28
27.5
M20
2.5
21.7
21.4
45
2.5
14
13.5
32
35
34.5
M24
3
27.7
27.4
56
4
18
17
41
44
43
M30
3.5
35.6
35.3
70
6
22
21
50
54
53
M36
4
41.6
41.3
82
6
26
25
60
65
64
M42
4.5
47.6
47.3
95
6
30
29
70
75
74
M48
5
53.6
53.2
110
6
34
33
80
85
84