Tap Drill Size Chart

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From my experience, finding the right drill size for screws or bolts can be really tricky without a handy tap drill chart. There’s a lot to consider, like threads per inch and drill diameter. But don’t worry, I’ve put together all the key info in a simple table for you.

THREAD SIZE

FRACTIONAL (in.)

 

DRILL DIAMETER

 

TAP DRILL SIZE

Coarse Thread

1/64

.0595

No. 53

2-56

.0700

No. 50

3-48

.0785

No. 47

4-40

3/32”

.0890

No. 43

5-40

.1015

No. 38

6-32

7/64”

.1065

No. 36

8-32

.1360

No. 29

10-24

5/32”

.1495

No. 25

12-24

11/64”

.1770

No. 16

1/4-20

13/64”

.2010

No. 7

5/16-18

17/64”

.2570

‘F’

3/8-6

1 7/32”

1.2188

3/8-16

5/16”

.3125

5/16

7/16-14

23/64”

.3680

‘U’

1/2-13

27/64”

.4219

27/64

9/16-12

31/64”

.4844

31/64

5/8-11

17/32”

.5312

17/32

3/4-10

21/32”

.6562

21/32

7/8-9

.7656

49/64

1″-8

.8750

7/8

1-1/2

1.882

1-25/32”

1 1/2 6

1 11/32”

1.3438

1 1/4-7

1 7/64”

1.1094

Fine Thread

0-80

3/64”

.0469

3/64

1-72

.0595

No. 53

2-64

.0700

No. 50

3-56

.0820

No. 45

4-48

.0935

No. 42

5-44

.1040

No. 37

6-40

.1130

No. 33

8-36

.1360

No. 29

10-32

5/32”

.1590

No. 21

12-28

.1820

No. 14

1/4-28

7/32”

.2130

No. 3

5/16-24

.2720

‘I’

3/8-24

21/64”

.3320

‘Q’

7/16-20

25/64”

.3906

25/64

1/2-20

29/64”

.4531

29/64

9/16-18

33/64”

.5156

33/64

5/8-18

37/64”

.5781

37/64

3/4-16

11/16”

.6875

11/16

7/8-14

.8125

13/16

1″-14

.9375

59/64

NS (Special Thread)

7/8 -18 

53/64”

.8281

53/64”

11/16-11

19/32”

.5938

1-14

15/16”

.9375

NEF (Ultra Fine Thread)

5/16-32

9/32”

.2812

8/32”

*Drill sizes are for 75% of the total depth of the thread.

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Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.

Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.

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