材质 
M12
1.75
10.8
10.37
22
21.16
20.1
M14
2
12.8
12.1
24
23.16
21.86
M16
2
14.8
14.1
27
26.16
24.9
M18
2.5
15.8
15.1
30
29.16
27.7
M20
2.5
18
16.9
32
31
29.5
M22
2.5
19.4
18.1
36
35
33.3
M24
3
21.5
20.2
41
40
38
M27
3
23.8
22.5
46
45
42.8
M30
3.5
25.6
24.3
50
49
46.6
M36
4
31
29.4
60
58.8
55.9