材质 
M10
1.5
22.3
10
9.78
16.32
17.32
8.6
15
14.57
M12
1.75
26.6
12
11.73
19.68
20.78
10.4
18
17.57
M14
2
30.5
14
13.73
22.94
24.25
12.4
21
20.48
M16
2
35
16
15.73
25.94
27.71
14.1
24
23.16
M20
2.5
43
20
19.67
32.66
34.64
17.7
30
29.16