27.835
27.9
细
0.5
4.599
4.459
4.5
1.5
28.626
28.376
28.5
M6
粗
1
5.118
4.918
5.0
1
29.118
28.918
29.0
细
0.75
5.378
5.118
5.2
M33
粗
3.5
29.6
6.887
6.647
6.7
细
2
31.135
30.835
14.397
12.918
3/4
10
16.3
16.4
2.540
19.050
17.424
15.798
7/8
9
19.1
19.3
2.822
22.225
20.418
18.611
1
8
21.9
22.0
3.175
25.400
23.367
21.334
11/8
7
24.6
24.7
3.629
28.575
26.252
23.929
30.9
细
1
7.118
6.918
7.0
1.5
31.626
31.376
31.8
0.75
7.378
7.118
7.2
M36
粗
4
32.15
31.67
31.8
M10
粗
1.5
8.626
8.376
8.5
细
3
33.132
32.752
32.9
细
1.25
8.867
8.647
8.7
2
34.135
33.835
33.9
1
9.118
22.918
23.0
1.5
46.626
46.376
46.5
英寸制螺纹钻底孔的钻头尺寸表
钻底孔钻头直径的计算公式:
螺纹公称直径
铸铁与青铜
钢与黄铜
3/16”~5/8”
dT=25(d-1/n)
dT=25(d-1/n)+0.1
3/4”~11/2”
dT=25(d-1/n)
dT=25(d-1/n)+0.2
注: dT-攻螺纹前钻头直径(mm)
5/16
18
6.4
6.5
1.411
7.938
7.034
6.131
3/8
16
7.8
7.9
1.588
9.525
8.509
7.492
7/16
14
9.1
9.3
1.814
11.112
9.951
8.789
1/2
12
10.4
10.5
2.117
12.700
11.345
9.989
5/8
11
13.3
13.5
2.309
15.875
14.918
15.0
1.5
40.626
40.376
40.5
M20
粗
2.5
17.634
17.294
17.4
M45
粗
4.5
40.679
40.129
40.3
细
2
18.135
17.835
17.9
细
3
42.132
41.132
41.9
1.5
18.626
18.376
18.5
2
43.135
42.835
42.9
1
19.118
8.918
9.0
1.5
34.626
34.376
34.5
0.75
9.378
9.118
9.2
M39
粗
4
35.15
34.67
34.8
M12
粗
1.75
10.386
10.106
10.2
细
3
36.132
35.752
35.9
细
1.5
10.626
10.376
10.5
2
37.135
36.835
36.9
1.25
10.867
10.647
10.7
1.5
37.626
37.376
37.5
1
11.118
10.918
11.0
M42
粗
4.5
37.679
37.129
37.3
M16
粗
2
14.135
13.835
13.9
细
3
39.132
38.752
38.9
细
1.5
14.626
14.376
14.5
2
40.135
39.835
39.9
1
15.118
d-螺纹公称直径(寸)【说明】英寸制螺纹牙型角a为55°
n-每寸牙数
公称
直径d
(寸)
每寸
牙数
n
钻头直径dT
(mm)
螺距
P
(mm)
螺纹直径(mm)
铸铁
青铜
钢
黄铜
大径
dd
中径
d2
小径
d1
3/16
24
3.7
3.7
1.058
4.762
4.085
3.408
1/4
20
5.0
5.1
1.270
6.350
5.537
4.724
1.5
25.626
25.376
25.5
细
0.35
2.721
2.621
2.65
1
26.118
25.918
26.0
M4
粗
0.7
3.422
3.242
3.3
M30
粗
3.5
26.631
26.211
26.3
细
0.5
3.599
3.459
3.5
细
3
26.9
26.88
26.7
M5
粗
0.8
4.334
4.134
4.2
2
28.135
41.4
41.5
5.644
47.625
44.011
40.397
2
41/2
44.6
44.7
5.644
50.800
47.186
43.572
21/4
4
50.0
50.2
6.350
57.150
53.084
49.019
21/2
4
56.3
56.5
6.350
63.500
59.434
55.369
23/4
31/2
61.6
(mm)
螺纹直径d
螺距
p
螺纹内径
推荐钻头直径dT
螺纹直径d
螺距
p
螺纹内径
推荐钻头直径dT
Max
Min
Max
Min
M2
粗
0.4
1.677
1.567
1.6
M27
粗
3
24.132
23.752
23.9
细
0.25
1.809
1.729
1.75
细
2
25.135
24.835
24.9
M3
粗
0.5
2.599
2.459
2.5
18.918
19.0
1.5
43.626
43.376
43.5
M24
粗
3
21.132
20.752
20.9
M48
粗
5
43.118
42.588
42.7
细
2
22.135
21.835
21.9
细
3
45.132
44.752
44.8
1.5
22.626
22.376
22.5
2
46.135
45.835
45.9
1
23.118
85.6
8.467
95.250
89.829
84.409
4
3
91.7
91.9
8.467
11/4
7
27.8
27.9
3.629
31.750
29.427
27.104
11/2
6
33.4
33.5
4.233
38.100
35.390
32.679
15/8
5
35.7
35.8
5.080
41.275
38.022
34.770
13/4
5
38.9
39.0
5.080
44.450
41.198
37.945
17/8
41/2
61.8
7.257
69.850
65.204
60.557
3
31/2
67.9
68.1
7.257
76.200