Drill Sizes for Tapping
World Class Cutting Tools
METRIC (60° INCLUDED ANGLE)
Nominal
Diameter
Metric Coarse
Metric
Pitch
1
1.1
1.2
1.4
1.6
1.8
2
2.2
2.3
2.5
2.6
3
3.5
4
4.5
5
5
5.5
6
7
8
8
9
9
10
10
10
11
11
12
12
12
14
0.25
0.25
0.25
0.30
0.35
0.35
0.40
0.45
0.40
0.45
0.45
0.50
0.60
0.70
0.75
0.80
--1.00
1.00
1.25
-1.25
-1.50
--1.50
-1.75
--2.00
Nominal
Diameter
Metric Fine
Drill Size in mm
Fluted
Fluteless
0.75
-0.85
-0.95
-1.10
-1.25
-1.45
-1.60
-1.75
-1.90
-2.05
-2.15
-2.50
2.75
2.90
-3.30
3.70
3.70
-4.20
4.60
----5.00
5.50
6.00
-6.80
7.40
--7.80
---8.50
9.30
----9.50
---10.20
11.10
----12.00
--
Drill Size
in mm
------1.75
1.95
-2.15
-2.65
-3.50
4.00
4.50
4.25
5.00
5.25
6.25
7.25
7.00
8.25
8.00
9.25
9.00
8.75
10.00
9.75
11.00
10.75
10.50
13.00
Pitch
------0.25
0.25
-0.35
-0.35
-0.50
0.50
0.50
0.75
0.50
0.75
0.75
0.75
1.00
0.75
1.00
0.75
1.00
1.25
1.00
1.25
1.00
1.25
1.50
1.00
Metric Coarse
Metric
Pitch
14
14
15
15
16
16
17
18
18
18
18
20
20
20
22
22
22
24
24
24
25
25
25
27
27
28
28
30
30
30
30
32
32
----2.00
--2.50
---2.50
--2.50
--3.00
-----3.00
---3.50
------
Drill Size
in mm
----14.00
--15.50
---17.50
--19.50
--21.00
-----24.00
---26.50
------
UNIFIED NATIONAL THREADS (60° INCLUDED ANGLE)
Nominal
Dia
U.N.C.
Fractional
Size
TPI Drill
in mm
& Size
64
1.55
1
56
1.85
2
48
2.10
3
40
2.35
4
40
2.65
5
32
2.85
6
32
3.50
8
24
3.90
10
24
4.50
12
--1/8"
20
5.10
1/4"
18
6.60
5/16"
16
8.00
3/8"
14
9.40
7/16"
13
10.80
1/2"
12
12.20
9/16"
11
13.50
5/8"
16.50
10
3/4"
19.50
9
7/8"
22.25
8
1"
25.00
7
1.1/8"
28.00
7
1.1/4"
30.75
6
1.3/8"
34.00
6
1.1/2"
--1.5/8"
39.50
5
1.3/4"
45.00
4 1/2
2"
U.N.F.
TPI
72
64
56
48
44
40
36
32
28
-28
24
24
20
20
18
18
16
14
12
12
12
12
12
-----
N.P.S
Drill Size
in mm
1.55
1.90
2.15
2.40
2.70
2.95
3.50
4.10
4.70
-5.50
6.90
8.50
9.90
11.50
12.90
14.50
17.50
20.40
23.25
26.50
29.50
32.75
36.00
-----
TPI
---------27
18
-18
-14
--14
-11.50
-11.50
-11.50
--11.50
Drill Size
in mm
---------9.10
11.90
-15.25
-19.00
--27.00
-30.00
-39.50
-45.50
--62.00
---40
-32
32
24
-27
18
-18
-14
--14
-11.50
-11.50
-11.50
--11.50
Drill Size
in mm
---------8.70
11.10
-14.70
-18.25
--23.40
-29.40
-38.10
-44.00
--56.30
Nominal
Dia
Fractional
1/16"
3/32"
1/8"
5/32"
3/16"
7/32"
1/4"
5/16"
3/8"
7/16"
1/2"
9/16"
5/8"
3/4"
7/8"
1"
1.1/8"
1.1/4"
1.3/8"
1.1/2"
1.5/8"
1.3/4"
1.7/8"
2"
BRITISH STANDARD CYCLE (60° INCLUDED ANGLE)
Size
TPI
1/8"
5/32"
3/16"
7/32"
1/4"
9/32“
40
32
32
26
26
26
Drill Size
in mm
2.65
3.30
4.20
4.80
5.60
6.35
Size
TPI
5/16"
3/8"
7/16"
1/2"
9/16"
9/16"
26
26
26
26
20
26
Drill Size
in mm
7.10
8.70
10.30
11.90
13.30
13.50
Size
TPI
5/8"
11/16"
3/4"
1"
1.370"
1.450"
26
26
26
24
24
26
Drill Size
in mm
15.00
16.70
18.20
24.50
34.00
36.00
Pitch
1.25
1.50
1.00
1.50
1.00
1.50
1.50
1.00
1.25
1.50
2.00
1.00
1.50
2.00
1.00
1.50
2.00
1.00
1.50
2.00
1.00
1.50
2.00
1.50
2.00
1.50
2.00
1.00
1.50
2.00
3.00
1.50
2.00
Drill Size
in mm
12.75
12.50
14.00
13.50
15.00
14.50
15.50
17.00
16.75
16.50
16.00
19.00
18.50
18.00
21.00
20.50
20.00
23.00
22.50
22.00
24.00
23.50
23.00
25.50
25.00
26.50
26.00
29.00
28.50
28.00
27.00
30.50
30.00
Nominal
Diameter
Metric Fine
Metric Coarse
Metric
Pitch
33
33
33
35
36
36
36
38
38
39
39
39
40
40
42
42
42
42
45
45
45
48
48
48
48
50
52
52
52
56
60
64
68
3.50
---4.00
----4.00
----4.50
---4.50
--5.00
----5.00
--5.50
5.50
6.00
6.00
Drill Size
in mm
29.50
---32.00
----35.00
----37.50
---40.50
--43.00
----47.00
--50.50
54.50
58.00
62.00
Drill Size
in mm
31.50
31.00
30.00
33.50
34.50
34.00
33.00
36.50
36.00
37.50
37.00
36.00
38.00
37.00
40.50
40.00
39.00
38.00
43.50
43.00
42.00
46.50
46.00
45.00
44.00
47.00
50.00
49.00
48.00
-----
Pitch
1.50
2.00
3.00
1.50
1.50
2.00
3.00
1.50
2.00
1.50
2.00
3.00
2.00
3.00
1.50
2.00
3.00
4.00
1.50
2.00
3.00
1.50
2.00
3.00
4.00
3.00
2.00
3.00
4.00
-----
BRITISH STANDARD WHITWORTH THREADS
(55° INCLUDED ANGLE)
N.P.T
TPI
Metric Fine
B.S.W.
B.S.F.
Size
TPI Drill
in mm
1.20
60
1.90
48
2.55
40
3.20
32
3.70
24
4.50
24
5.10
20
6.50
18
7.90
16
9.30
14
10.50
12
12.10
12
13.50
11
16.25
10
19.25
9
22.00
8
7
24.75
7
28.00
6
30.10
6
33.50
5
35.70
5
39.00
4 1/2
41.30
4 1/2
44.50
B.S.B.
B.S.P.
B.S.P.T.
Size TPI Drill Size TPI Drill Size TPI
TPI Drill
in mm
in mm
in mm
--------------8.80
28
28
----------------4.00
32
-----4.60
28
11.80
19
19
5.30
26
5.30
26
---6.90
26
6.80
22
15.25
19
19
8.40
26
8.30
20
---10.00
26
9.70
18
19.00
14
14
11.70
26
11.10
16
---13.30
26
12.70
16
21.00
14
-15.00
26
14.00
14
24.50
14
14
18.00
26
16.75
12
28.25
14
-21.25
26
19.75
11
30.75
11
11
24.50
26
22.75
10
-----25.50
9
39.50
11
11
--28.50
9
-----31.50
8
45.00
11
11
--34.50
8
-----37.70
8
51.00
11
---41.00
7
-------57.00
11
11
--47.00
7
Drill Size
in mm
--8.40
---11.20
-14.75
-18.25
--23.75
-30.00
-38.50
-44.50
---56.00
BRITISH ASSOCIATION (47½° INCLUDED ANGLE)
Size
0
1
2
3
4
5
Nominal
Diameter
6.0
5.3
4.7
4.1
3.6
3.2
Pitch
1.00
0.90
0.81
0.73
0.66
0.59
Drill Size
in mm
5.10
4.50
4.00
3.40
3.00
2.65
Size
6
7
8
9
10
12
Nominal
Diameter
2.8
2.5
2.2
1.9
1.7
1.3
Pitch
Drill Size
in mm
0.53
0.48
0.43
0.39
0.35
0.28
2.30
2.05
1.80
1.55
1.40
1.05