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Metric Course Thread Drilling Chart

Thread Size Tap Drill (mm) Thread Size Tap Drill (mm) Thread Size Tap Drill (mm) Thread Size Tap Drill (mm)

M1 x 0.25

0.75

M3.5 x 0.6

2.90

M12 x 1.75

10.20

M36 x 4

32.00

M1.1 x 0.25

0.85

M4 x 0.7

3.30

M14 x 2

12.00

M39 x 4

35.00

M1.2 x 0.25

0.95

M4.5 x 0.75

3.70

M16 x 2

14.00

M42 x 4.5

37.50

M1.4 x 0.3

1.10

M5 x 0.8

4.20

M18 x 2.5

15.50

M45 x 4.5

40.50

M1.6 x 0.35

1.25

M6 x 1

5.00

M20 x 2.5

17.50

M48 x 5

43.00

M1.8 x 0.35

1.45

M7 x 1

6.00

M22 x 2.5

19.50

M52 x 5

47.00

M2 x 0.4

1.60

M8 x 1.25

6.80

M24 x 3

21.00

M56 x 5.5

50.50

M2.2 x 0.45

1.75

M9 x 1.25

7.80

M27 x 3

24.00

M60 x 5.5

54.50

M2.5 x 0.45

2.05

M10 x 1.5

8.50

M30 x 3.5

26.50

M64 x 6

58.00

M3 x 0.5

2.50

M11 x 1.5

9.50

M33 x 3.5

29.50

M68 x 6

62.00

 

Metric Fine Thread Drilling Chart

Thread Size Tap Drill (mm) Thread Size Tap Drill (mm) Thread Size Tap Drill (mm) Thread Size Tap Drill (mm)

M4 x 0.35

3.60

M10 x 0.75

9.25

M16 x 1

15.0

M24 x 1.5

22.5

M4 x 0.5

3.50

M10 x 1

9.0

M16 x 1.5

15.0

M24 x 2

22.0

M5 x 0.5

4.50

M10 x 1.25

8.8

M18 x 1

17.0

M26 x 1.5

24.5

M6 x .5

5.50

M11 x 1

10.0

M18 x 2

16.0

M27 x 1.5

25.5

M6 x .75

5.25

M12 x .75

11.25

M20 x 1

19.0

M27 x 2

25.0

M7 x .75

6.25

M12 x 1

11.0

M20 x 1.5

18.5

M28 x 1.5

26.5

M8 x .5

7.00

M12 x 1.5

10.5

M20 x 2

18.0

M30 x 1.5

28.5

M8 x .75

7.25

M14 x 1

13.0

M22 x 1

21.0

M30 x 2

28.0

M8 x 1

7.50

M14 x 1.25

12.8

M22 x 1.5

20.5

M33 x 2

31.0

M9 x 1

8.00

M14 x 1.5

12.5

M22 x 2

20.0

M36 x 3

33.0

Imperial

UNC

Tap Size Drill Size
1/4-20NC #8
5/16-18NC F
3/8-16NC 5/16
7/16-14NC U
1/2-13NC 27/64
9/16-12NC 31/64
5/8-11NC 14mm
3/4-10NC 21/32
7/8-9NC 49/64
1-8NC 7/8
1 1/8-7NC 63/64
1 1/4-7NC 1-7/64
1 3/8-6NC 1-3/16
1 1/2-6NC 1-11/32

UNF

Tap Size Drill Size
1/4-28NF #3
5/16-24NF I
3/8-24NF Q
7/16-20NF W
1/2-20NF 29/64
9/16-18NF 33/64
5/8-18NF 37/64
3/4-16NF 11/16
7/8-14NF 13/16
1-12NF 29/32
1 1/8-12NF 1-3/64
1 1/4-12NF 1-11/64
1 3/8-12NF 1-19/64
1 1/2-12NF 1-27/64

 

NS

 

 

Tap Size Drill Size
5/32-32NS 1/8
5/32-36NS #30
3/16-24NS #26
3/16-32NS #22
7/32-24NS #16
7/32-32NS #12
1/4-32NS 7/32
1/4-40NS #1
5/16-32NS 9/32
11/16-16NS 5/8
1-14NS 15/16

 

 

NPT

 

 

Tap Size Drill Size
1/8-27NPT R
1/4-18NPT 7/16
3/8-18NPT 15mm
1/2-14NPT 23/32
3/4-14NPT 59/64
1 x11-1/2NPT 1-5/32
1-1/4×11-1/2NPT 1-1/2
1-1/2×11-1/2NPT 1-47/64
2x 11-1/2NPT 2-7/32

This information is for a suggested reference only. We accept no responsibility for the above charts. 
Source: Steven L Henderson’s Cutting Edge Designs
Source: WLFuller