US Tap and Drill Bit Size Equivalents

U.S. Tap and Drill Bit Size http://www.boltdepot.com/http://www.boltdepot.com/ 

Tap 0-80 1-64 2-56 3-48 4-40 5-40 6-32 8-32 10-24 10-32 12-24 1/4-20 1/4-28 5/16-18 5/16-24 3/8-16 3/8-24 7/16-14 7/16-20 1/2-13 1/2-20 9/16-12 9/16-18 5/8-11 5/8-18 3/4-10 3/4-16

Fractional Number Drill Letter Drill Drill Bit Bit Bit 3/64 3/32 7/64 5/32 5/32 11/64 13/64 7/32 17/64 5/16 21/64 23/64 25/64 27/64 29/64 31/64 33/64 17/32 37/64 21/32 11/16

Drill sizes are for 75% depth of thread.

53 50 47 43 38 35 29 25 21 16 7 3 -

F I Q U -

Wood Screw Pilot Hole Size Screw Size

Hard Wood

Soft Wood

Countersink Size

Tapered Bit

Straight Bit

Tapered Bit

Straight Bit

2

3/32

1/16

5/64

1/16

1/4

3

7/64

5/64

3/32

1/16

1/4

4

7/64

5/64

3/32

1/16

1/4

5

1/8

3/32

7/64

5/64

5/16

6

9/64

7/64

1/8

3/32

5/16

7

5/32

7/64

9/64

3/32

5/16

8

11/64

1/8

5/32

7/64

3/8

9

3/16

9/64

11/64

1/8

3/8

10

13/64

9/64

3/16

1/8

7/16

12

7/32

5/32

13/64

9/64

7/16

14

1/4

11/64

15/64

5/32

1/2

16

9/32

3/16

17/64

11/64

9/16

18

5/16

7/32

19/64

13/64

5/8

20

21/64

15/64

5/16

7/32

3/4

24

3/8

17/64

3/8

1/4

3/4

US Recommended Bolt Torque Recommended Torque Size

Grade 5

Grade 8

18-8 S/S

Coarse

Fine

Coarse

Fine

Coarse

#4*

-

-

-

-

5.2

-

#6*

-

-

-

-

9.6

#8*

-

-

-

-

#10*

-

-

-

1/4

8

10

5/16

17

3/8

Bronze Fine

Coarse

Fine

4.8

-

4.3

-

-

8.9

-

7.9

-

19.8

-

18.4

-

16.2

-

-

22.8

31.7

21.2

29.3

18.6

25.9

12

14

6.3

7.8

5.7

7.3

5.1

6.4

19

24

27

11

11.8

10.3

10.9

8.9

9.7

31

35

44

49

20

22

18

20

16

18

7/16

49

55

70

78

31

33

29

31

26

27

1/2

75

85

105

120

43

45

40

42

35

37

9/16

110

120

155

170

57

63

53

58

47

51

5/8

150

170

284

323

93

104

86

96

76

85

3/4

270

295

510

568

128

124

104

102

118

115

7/8

395

435

813

902

194

193

178

178

159

158

1

590

660

905

1030

287

289

265

240

235

212

* Sizes from 4 to 10 are in in.-lbs. Sizes from 1/4 up are in Ft. -lbs.

Fine Coarse

Brass

Metric Recommended Bolt Torque Diameter

Recommended Torque (N*m) Class 8.8

Class 10.9

5

7

9

6

12

16

8

30

40

10

55

75

12

100

135

14

160

215

16

245

335

20

480

650

Metric Tap and Drill Bit Size Tap

Metric Drill

US Drill

3mm x 0.6

2.5mm

-

4mm x 0.7

3.4mm

-

5mm x 0.8

4.3mm

-

6mm x 1.0

5.2mm

-

7mm x 1.0

6.1mm

15/64

8mm x 1.25

6.9mm

17/64

8mm x 1.0

7.1mm

-

10mm x 1.5

8.7mm

-

10mm x 1.25

8.9mm

11/32

10mm x 1.0

9.1mm

-

12mm x 1.75

10.5mm

-

12mm x 1.5

10.7mm

27/64

14mm x 2.0

12.2mm

-

14mm x 1.5

12.7mm

-

16mm x 2.0

14.2mm

35/64

16mm x 1.5

14.7mm

-

Drill sizes are for 75% depth of thread.

US to Metric Conversion US Metric (Nearest millimeters 32nd)

US Metric (Nearest millimeters 32nd)

2

3/32

55

2-3/16

2.5

3/32

60

2-3/8

3

1/8

65

2-9/16

4

5/32

70

2-3/4

5

3/16

75

2-15/16

6

1/4

80

3-1/8

8

5/16

85

3-3/8

10

13/32

90

3-9/16

12

15/32

95

3-3/4

14

9/16

100

3-15/16

16

5/8

110

4-5/16

18

23/32

120

4-3/4

20

25/32

130

5-1/8

25

1

140

5-1/2

30

1-3/16

150

5-7/8

35

1-3/8

160

6-6/16

40

1-9/16

170

6-11/16

45

1-3/4

180

7-1/16

50

2

190

7-1/2

US Threads Per Inch Threads Per Inch (TPI) Bolt Size

Coarse Thread UNC

Fine Thread UNF

#2

56

-

#3

48

-

#4

40

-

#5

40

-

#6

32

-

#8

32

-

#10

24

32

#12

24

-

1/4

20

28

5/16

18

24

3/8

16

24

7/16

14

20

1/2

13

20

9/16

12

18

5/8

11

18

3/4

10

16

7/8

9

14

1

8

14

1-1/8

7

12

1-1/4

7

12

1-1/2

6

12

Metric Thread Pitch Thread Pitch

Bolt Diameter

Standard

Fine

Extra or Super Fine

JIS

2

.4

-

-

.4

2.5

.45

-

-

.45

3

.5

-

-

.5

4

.7

-

-

.7

5

.8

-

-

.8

6

1.0

-

-

1.0

7

1.0

-

-

1.0

8

1.25

1

-

1.0

10

1.5

1.25

1

1.25

12

1.75

1.5

1.25

1.25

14

2

1.5

-

1.5

16

2

-

-

1.5

18

2.5

-

-

1.5

20

2.5

-

-

1.5