材质 
M12
1.75
23.91
10.8
10.37
22
21.16
M14
2
27.12
12.8
12.10
24
23.16
M16
2
29.56
14.8
14.10
27
26.16
M18
2.5
32.95
15.8
15.10
30
29.16
M20
2.5
35.03
18
16.90
32
31
M22
2.5
39.55
19.4
18.10
36
35
M24
3
45.2
21.5
20.20
41
40
M27
3
50.85
23.8
22.50
46
45
M30
3.5
55.37
25.6
24.3
50
49
M36
4
66.44
31
29.4
60
58.8