材质 
M3
0.5
6
8.63
3.5
8
M6
1
7.2
10.89
4
10
M8
1.25
10.2
14.2
5.5
13
M10
1.5
12.2
18.72
7
17
M12
1.75
15.2
20.88
8
19
M16
2
19.2
26.17
10
24
M20
2.5
24.4
32.95
13
30
M24
3
28.4
39.55
15
36