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TAP-DRILL CHART

RECOMMEND TAP DRILL TO USE FOR 75% DEPTH OF THREAD

To Tap This Size Screw Or Bolt:

Use This Drill Bit:

(Closest Fractional:)

Decimal Inches

0-80 NF

3/64"

3/64"

.0469

1-64 NC

#53

-

.0595

1-72 NF

#53

1/16"

.0595

2-56 NC

#50

-

.0700

2-64 NF

#50

-

.0700

3-48 NC

#47

5/64"

.0785

3-56 NF

#45

-

.0820

4-36 NS

#44

-

.0860

4-40 NC

#43

3/32"

.0890

4-48 NF

#42

3/32"

.0935

3mm-0.60mm

2.5mm

-

.0984

1/8-40 NS

#38

-

.1015

5-40 NC

#38

-

.1015

5-44 NF

#37

-

.1040

6-32 NC

#35

7/64"

.1100

6-36 NS

#34

-

.1110

6-40 NF

#33

-

.1130

6-48 NS

#31

-

.1200

4mm-0.70mm

3.4mm

-

.1338

4mm-0.75mm

3.4mm

-

.1338

8-32 NC

#29

-

.1360

8-36 NF

#29

9/64"

.1360

8-40 NS

#28

-

.1405

3/16-24 NS

#26

-

.1470

10-24 NC

#25

5/32"

.1495

3/16-32 NS

#22

-

.1570

10-32 NF

#21

5/32"

.1590

5mm-0.90mm

4.2mm

-

.1653

5mm-0.80mm

4.3mm

-

.1693

12-24 NC

#16

11/64"

.1770

12-28 NF

#14

3/16"

.1820

12-32 NEF

#13

-

.1850

14-20 NS

#10

-

.1935

1/4-20 NC

#7

13/64"

.2010

14-24 NS

#7

-

.2010

6mm-1.00mm

5.2mm

-

.2047

1/4-24 NS

#4

-

.2090

1/4-28 NF

#3

7/32"

.2130

1/4-32 NEF

7/32"

7/32"

.2188

1/4-40 NS

#1

-

.2280

7mm-1.00mm

6.1mm

15/64"

.2401

5/16-18 NC

Ltr.F

17/64"

.2570

8mm-1.25mm

6.9mm

17/64"

.2716

5/16-24 NF

Ltr.I

-

.2720

8mm-1.00mm

7.1mm

-

.2795

5/16-32 NEF

9/32"

9/32"

.2812

9mm-1.25mm

7.9mm

-

.3110

3/8-16 NC

5/16"

5/16"

.3125

 

* These Sizes Are Spark Plug Taps

 

To Tap This Size Screw Or Bolt:

Use This Drill Bit:

(Closest Fractional:)

Decimal Inches

9mm-1.00mm

8.1mm

-

.3189

9mm-0.75mm

8.3mm

-

.3268

3/8-24 NF

Ltr.Q

21/64"

.3320

10mm-1.50mm

8.7mm

-

.3425

10mm-1.25mm

8.9mm

11/32"

.3503

10mm-1.00mm*

9.1mm

-

.3583

7/16-14 NC

Ltr.U

23/64"

.3680

11mm-1.50mm

9.7mm

-

.3818

7/16-20 NF

25/64"

25/64"

.3906

12mm-1.75mm

10.5mm

-

.4133

12mm-1.50mm

10.7mm

27/64"

.4212

1/2-13 NC

27/64"

27/64"

.4219

12mm-1.25mm*

10.9mm

27/64"

.4291

1/2-20 NF

29/64"

29/64"

.4531

1/2-24 NS

29/64"

29/64"

.4531

14mm-2.00mm

12.2mm

-

.4803

9/16-12 NC

31/64"

31/64"

.4844

14mm-1.50mm

12.7mm

-

.4999

14mm-1.25mm*

12.8mm

-

.5039

9/16-18 NF

33/64"

33/64"

.5156

5/8-11 NC

17/32"

17/32"

.5312

16mm-2.00mm

14.2mm

35/64"

.5590

5/8-18 NF

37/64"

37/64"

.5781

16mm-1.50mm

14.7mm

-

.5787

11/16-11 NS

19/32"

19/32"

.5938

18mm-2.50mm

15.8mm

39/64"

.6220

11/16-16 NS

5/8"

5/8"

.6250

3/4-10 NC

21/32"

21/32"

.6562

18mm-1.50mm*

16.8mm

-

.6614

3/4-16 NF

11/16"

11/16"

.6875

20mm-2.50mm

17.8mm

11/16"

.7008

7/8-9 NC

49/64"

49/64"

.7656

7/8-14 NF

13/16"

13/16"

.8125

22mm-1.50mm

20.9mm

-

.8228

7/8-18 NS*

53/64"

53/64"

.8281

24mm-3.00mm

21.4mm

53/64"

.8425

1.8 NC

7/8"

7/8"

.8750

24mm-2.00mm

22.3mm

-

.8779

1.12 NF

59/64"

59/64"

.9219

1-14 NS

15/16"

15/16"

.9375

1 1/8-7 NC

63/64"

63/64"

.9844

1 1/8-12 NF

1 3/64"

1 3/64"

1.0469

1 1/4-7 NC

1 7/64"

1 7/64"

1.1094

1 1/4-12 NF

1 11/64"

1 11/64"

1.1719

1 3/8-6 NC

1 7/32"

1 7/32"

1.2188

1 3/8-12 NF

1 19/64"

1 19/64"

1.2969

1 1/2-6 NC

1 11/32"

1 11/32"

1.3438

1 1/2"-12 NF

1 27/64"

1 27/64"

1.4219