材质 
M12
1.75
12.85
12.74
22.78
8
0.8
21
M16
2
16.85
16.74
29.56
10
0.8
27
M20
2.5
20.84
20.71
37.29
13
1.2
34
M22
2.5
22.84
22.71
39.55
14
1.2
36
M24
3
24.84
24.71
45.2
15
1.2
41
M27
3
27.84
27.71
50.85
17
1.5
46
M30
3.5
30.83
30.67
55.37
19
1.5
50