螺栓孔径及沉头孔径的尺寸图标
螺纹公称直径 螺栓孔径dh 倒角e 沉头孔径d′
1级 2级 3级 4级*
2 2.2 2.4 2.6 - 0.3 7
3 3.2 3.4 3.6 - 0.3 9
4 4.3 4.5 4.8 (5.5) 0.4 11
5 5.3 5.5 5.8 (6.5) 0.4 13
6 6.4 6.6 7 (7.8) 0.4 15
8 8.4 9 10 (10) 0.6 20
10 10.5 11 12 (13) 0.6 24
12 13 13.5 14.5 (15) 1.1 28
14 15 15.5 16.5 (17) 1.1 32
16 17 17.5 18.5 (20) 1.1 35
18 19 20 21 (22) 1.1 39
20 21 22 24 (25) 1.2 43
22 23 24 26 (27) 1.2 46
24 25 26 28 (29) 1.2 50