材质 
M16
2
26.17
25
24.16
24
23.16
M18
2.5
29.56
28
27.16
27
26.16
M20
2.5
32.95
32
30.4
30
29.16
M22
2.5
37.29
35
33.4
34
33
M24
3
39.55
38
36.4
36
35
M27
3
45.2
42
40.4
41
40
M30
3.5
50.85
48
46.4
46
45
M36
4
60.79
55
53.1
55
53.8
M42
4.5
72.09
65
63.1
65
63.8
M48
5
82.6
75
73.1
75
73.1