材质 
M12
1.75
12.7
11.8
8.8
7.2
22
21.2
25.4
30
25
M16
2
16.7
15.8
10.8
9.2
27
26.2
31.2
35
30
M20
2.5
20.8
19.6
13.9
12.1
32
31
37
41
35
M22
2.5
22.8
21.6
14.9
13.1
36
35
41.6
46
40
M24
3
24.8
23.6
15.9
14.1
41
40
47.3
51
45
M27
3
27.8
26.6
17.9
16.1
46
45
53.1
56
50
M30
3.5
30.8
29.6
20
18
50
49
57.7
61
55