本表所推选钻头孔径，是针对攻牙加工时，能够很容易的了解钻头直径，而依据市售的标准钻头所选定的，在使用钻头的情况下，由于钻头的形状及尺寸，精度，被钻孔的材质等，对于所钻孔的尺寸，精度有很大影响，所以使用本表的钻孔径，若有不当之处，应实际状况适当的变更钻头直径，本表依据2级牙制订。
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公制粗螺纹
|
|
规格
|
标准径
|
2级牙钻孔径
|
|
最大
|
最小
|
|
M1.0×0.25
|
0.75
|
0.785
|
0.729
|
|
M1.1×0.25
|
0.85
|
0.885
|
0.829
|
|
M1.2×0.25
|
0.95
|
0.985
|
0.929
|
|
M1.4×0.3
|
1.10
|
1.142
|
1.075
|
|
M1.6×0.35
|
1.25
|
1.321
|
1.221
|
|
M1.7×0.35
|
1.35
|
1.421
|
1.321
|
|
M1.8×0.35
|
1.45
|
1.521
|
1.421
|
|
M2.0×0.4
|
1.60
|
1.679
|
1.567
|
|
M2.2×0.45
|
1.75
|
1.838
|
1.713
|
|
M2.3×0.4
|
1.90
|
1.979
|
1.867
|
|
M2.5×0.45
|
2.10
|
2.138
|
2.013
|
|
M2.6×0.45
|
2.20
|
2.238
|
2.113
|
|
M3.0×0.5
|
2.50
|
2.599
|
2.459
|
|
M3.0×0.6
|
2.40
|
2.44
|
2.280
|
|
M3.5×0.6
|
2.90
|
3.010
|
2.850
|
|
M4.0×0.7
|
3.30
|
3.422
|
3.242
|
|
M4.0×0.75
|
3.25
|
3.326
|
3.106
|
|
M4.5×0.75
|
3.80
|
3.878
|
3.688
|
|
M5.0×0.8
|
4.20
|
4.334
|
4.134
|
|
M5.0×0.9
|
4.10
|
4.170
|
3.930
|
|
M6.0×1.0
|
5.00
|
5.153
|
4.917
|
|
M7.0×1.0
|
6.00
|
6.153
|
5.917
|
|
M8.0×1.25
|
6.80
|
6.912
|
6.647
|
|
M9.0×1.25
|
7.80
|
7.912
|
7.647
|
|
M10×1.5
|
8.50
|
8.676
|
8.376
|
|
M11×1.5
|
9.50
|
9.676
|
9.376
|
|
M12×1.75
|
10.30
|
10.441
|
10.106
|
|
M14×2.0
|
12.00
|
12.210
|
11.735
|
|
M16×2.0
|
14.00
|
14.210
|
13.835
|
|
M18×2.5
|
15.50
|
15.744
|
15.294
|
|
M20×2.5
|
17.50
|
17.744
|
17.294
|
|
M22×2.5
|
19.50
|
19.744
|
19.294
|
|
M24×3.0
|
21.00
|
21.252
|
2.752
|
|
M27×3.0
|
24.00
|
24.252
|
23.752
|
|
M30×3.5
|
26.50
|
26.771
|
26.211
|
|
