Tap Size

Drill Size

Drill in Decimal

% of Thread

0-80

#56

.0465

73

3/64"

.0469

71

1-64

#54

.0550

80

#53

.0595

59

1-72

#53

.0595

67

1/16"

.0625

50

2-56

#51

.0670

73

#50

.0700

62

2-64

#50

.0700

70

#49

.0730

56

3-46

#48

.0760

77

5/64"

.0781

70

3-56

#46

.0810

69

#45

.0820

65

4-40

#44

.0860

73

#43

.0890

65

4-48

#42

.0935

61

3/32"

.0938

60

5-40

#40

.0980

75

#38

.1015

65

5-44

#38

.1015

71

#37

.1040

63

Tap Size

Drill Size

Drill in Decimal

% of Thread

6-32

#37

.1040

77

7/64"

.1094

64

6-40

#34

.1110

74

#33

.1130

69

8-32

#29

.1360

62

#28

.1405

51

8-36

#29

.1360

70

9/64"

.1406

57

10-24

#27

.1440

78

#25

.1495

69

10-32

5/32"

1563

74

#21

.1590

68

12-24

11/64"

.1719

74

#17

.1730

73

12-28

#16

.1770

76

#15

.1800

70

Tap Size

Drill Size

Drill in Decimal

% of Thread

1/4-20

#7

.2010

70

13/64"

.2031

66

1/4-28

#3

.2130

72

7/32"

.2188

59

5/16-18

F

.2570

71

17/64"

.2656

59

5/16-24

H

.2660

77

I

.2720

67

3/8-16

5/16"

.3125

71

O

.3160

68

3/8-24

21/64"

.3281

78

Q

.3320

71

7/16-14

T

.3580

80

23/64"

.3594

79

7/16-20

W

.3860

71

25/64"

.3906

65

1/2-13

27/64"

.4219

72

7/16

.4375

58

1/2-20

29/64"

.4531

65

9/16-12

15/32"

.4688

80

31/64"

.4844

68

9/16-18

1/2"

.5000

78

33/64"

.5156

58