Machine Screw Size

Number of Threads Per Inch

Minor Dia.

Tap Drills

Clearance Hole Drills

Aluminum, Brass & Plastics

75% Thread 

Stainless Steel, Steels & Iron

50% Thread

All Materials

Close Fit

Free Fit

No. or Dia.

Major Dia.

Drill Size

Decimal Equiv.

Drill Size

Decimal Equiv.

Drill Size

Decimal Equiv.

Drill Size

Decimal Equiv.

8

.1640

32

.1257

29

.1360

27

.1440

18

.1695

16

.1770

36

.1299

29

.1360

26

.1470

10

.1900

24

.1389

25

.1495

20

.1610

9

.1960

7

.2010

32

.1517

21

.1590

18

.1695

12

.2160

24

.1649

16

.1770

12

.1890

2

.2210

1

.2280

28

.1722

14

.1820

10

.1935

32

.1777

13

.1850

9

.1960

1/4

.2500

20

.1887

7

.2010

7/32

.2188

F

.2570

H

.2660

28

.2062

3

.2130

1

.2280

32

.2117

7/32

.2188

1

.2280

5/16

.3125

18

.2443

F

.2570

J

.2770

P

.3230

Q

.3320

24

.2614

I

.2720

9/32

.2812

32

.2742

9/32

.2812

L

.2900

3/8

.3750

16

.2983

5/16

.3125

Q

.3320

W

.3860

X

.3970

24

.3239

Q

.3320

S

.3480

32

.3367

11/32

.3438

T

.3580