Tap Drill Sizes

CUT THREADS

Inch:

Actual
Drill Size
Needed

 

Major Dia.
(Basic)
of Tap

 

1.299 x % of Thread

 

Probable
Oversize of
Tap Drill

 

=

-


-

 

 

 

Pitch (# of Threads per Inch)

 

 

 

 

 

 

 

 

 

 

Metric:

Actual
Drill Size
Needed
mm

 

Major Dia.
(Basic)
of Tap
mm

 

1.299 x % of Thread x Pitch (mm)

 

Probable
Oversize of
Tap Drill

 

=

-


-

 

 

 

25.4

 

ROLL FORM THREADS

Inch:

Actual
Drill Size
Needed

 

Major Dia.
(Basic)
of Tap

 

0.680 x % of Thread

 

Probable
Oversize of
Tap Drill

 

=

-


-

 

 

 

Pitch (# of Threads per Inch)

 

 

 

 

 

 

 

 

 

 

Metric:

Actual
Drill Size
Needed
mm

 

Major Dia.
(Basic)
of Tap
mm

 

1.299 x % of Thread x Pitch (mm)

 

Probable
Oversize of
Tap Drill

 

=

-


-

 

 

 

25.4

 

When you know the hole size and you want to know what % of thread you are producing:

Inch:

% of
Thread

 

Major Dia.
of Tap

 

Major Dia.
of Tap

-

Actual
Hole Size

 

Pitch
(Threads per Inch)

 

=

-


x

 

 

 

Pitch (# of Threads per Inch)

 

 

 

 

 

 

 

 

 

Metric:

% of
Thread

 

Major Dia.
of Tap
mm

 

Major Dia.
of Tap (mm)

-

Actual
Hole Size (mm)

 

 

 

=

-


 

 

 

 

25.4

 

 

TAP SIZE

" B "
Major Dia.
Basic
All Tread Classes

" B "
Major
Dia.

Basic
Metric

Unified 3B
ASME B1.1

Cut Tap
min / max

Unified 2B
ASME B1.1

Cut Tap
min / max

Mil-S-8879
3B A/B/C

Cut Tap
min / max

Inch


Roll Tap
min / max

Metric 6H
ASME B1.13M

Cut Tap
min / max

Metric


Roll Tap
min / max

0 - 80

.0600

-

.0465-.0514

.0465 - .0514

.0479 - .0511

.0546 - .0558

-

-

M1.6 x 0.35

.0629

1.6mm

-

-

-

-

.0480 - .0520

.0561 - .0578

1 - 64

.0730

-

.0561 - .0623

.0561 - .0623

.0578 - .0619

.0660 - .0680

-

-

1 - 72

.0730

-

.0580 - .0635

.0580 - .0635

.0595 - .0631

.0670 - .0690

-

-

M2 x 0.4

.0787

2.0mm

-

-

-

-

.0616 - .0661

.0709 - .0728

2 - 56

.0860

-

.0667 - .0737

.0667 - .0737

.0686 - .0732

.0780 - .0800

-

-

2 - 64

.0860

-

.0691 - .0753

.0691 - .0753

.0708 - .0749

.0790 - .0810

-

-

M2.5 x 0.45

.0984

2.5mm

-

-

-

-

.0792 - .0841

.0896 - .0918

3 - 48

.0990

-

.0764 - .0845

.0764 - .0845

.0900 - .0920

.0900 - .0920

-

-

3 - 56

.0990

-

.0797 - .0845

.0797 - .0855

.0910 - .0930

.0910 - .0930

-

-

4 - 40

.1120

-

.0849 - .0939

.0849 - .0939

.1000 - .1030

.1000 - .1030

-

-

4 - 48

.1120

-

.0894 - .0968

.0890 - .0968

.1030 - .1050

.1030 - .1050

-

-

M3 x 0.5

.1181

3.0mm

-

-

-

-

.0968 - .1023

.1087 - .1107

5 - 40

.1250

-

.0979 - .1062

.0979 - .1062

.1130 - .1160

.1130 - .1160

-

-

M 3.5 x 0.6

.1378

3.5mm

-

-

-

-

.1122 - .1185

.1260 - .1289

6 - 32

.1380

-

.1040 -.1140

.1040 - .1140

.1240 - .1260

.1240 - .1260

-

-

6 - 40

.1380

-

.1110 - .1186

.1110 - .1190

.1260 - .1280

.1260 - .1280

-

-

M4 x 0.7

.1574

4.0 mm

-

-

-

-

.1276 - .1347

.1437 - .1471

8 - 32

.1640

-

.1300 - .1389

.1300 - .1390

.1336 - .1417

.1490 - .1520

-

-

8 - 36

.1640

-

.1340 - .1416

.1340 - .1420

.1370 - .1442

.1510 - .1530

-

-

10 - 24

.1900

-

.1450 - .1555

.1450 - .1560

.1494 - .1600

.1700 - .1740

-

-

10 - 32

.1900

-

.1560 - .1641

.1560 - .1640

.1596 - .1675

.1750 - .1780

-

-

M5 x 0.8

.1968

5.0 mm

-

-

-

-

.1627 - .1706

.1811 - .1850

M6 x 1.0

.2362

6.0 mm

-

-

-

-

.1935 - .2028

.2165 - .2215

M6 x 0.75

.2362

6.0 mm

-

-

-

-

.2042 - .2117

-

1/4 - 20

.2500

-

.1960 - .2067

.1960 - .2070

.2013 - .2121

.2250 - .2300

-

-

1/4 - 28

.2500

-

.2110 - .2190

.2110 - .2200

.2152 - .2229

.2330 - .2370

-

-

5/16 - 18

.3125

-

.2520 - .2630

.2520 - .2650

.2584 - .2690

.2850 - .2910

-

-

5/16 - 24

.3125

-

.2670 - .2754

.2670 - .2770

.2719 - .2799

.2920 - .2970

-

-

M8 x 1.25

.3149

8.0mm

-

-

-

-

.2616 - .2721

.2904 - .2965

M8 x 1.0

.3149

8.0mm

-

-

-

-

.2723 -.2816

.2927 - .2725

3/8 - 16

.3750

-

.3070 - .3128

.3070 - .3210

.3192 - .3251

.3440 - .3500

-

-

3/8 - 24

.3750

-

.3300 - .3372

.3300 - .3400

.3344 - .3418

.3550 - .3590

-

-

M10 x 1.5

.3937

10.0mm

-

-

-

-

.3297 - .3415

.3642 - .3716

M10 x 1.25

.3937

10.0mm

-

-

-

-

.3404 - .3508

.3658 - .3712

7/16 - 14

.4375

-

.3600 - .3717

.3600 - .3760

.3680 - .3795

.4020 - .4090

-

-

7/16 - 20

.4375

-

.3830 - .3916

.3830 - .3950

.3888 - .3970

.4140 - .4180

-

-

M12 x 1.75

.4724

12.0 mm

-

-

-

-

.3978 - .4110

.4380 - .4466

M12 x 1.25

.4724

12.0mm

-

-

-

-

.4192 - .4295

.4445 - .4499

1/2 - 13

.5000

-

.4170 - .4284

.4170 - .4340

.4251 - .4368

.4620 - .4700

-

-

1/2 - 20

.5000

-

.4460 - .4537

.4460 - .4570

.4513 - .4591

.4750 - .4800

-

-

M14 x 2.0

.5511

14.0mm

-

-

-

-

.4659 - .4807

.5118 - .5217

M14 x 1.5

.5511

14.0mm

-

-

-

-

.4872 - .4990

.5177 - .5239

9/16 - 12

.5625

-

.4720 - .4843

.4720 - .4900

.4814 - .4914

.5200 - .5280

-

-

9/16 - 18

.5625

-

.5020 - .5106

.5020 - .5150

.5084 - .5156

.5350 - .5400

-

-

5/8 - 11

.6250

-

.5270 - .5391

.5270 - .5460

.5365 - .5474

.5790 - .5860

-

-

5/8 - 18

.6250

-

.5650 - .5730

.5650 - .5780

.5709 - .5788

.5980 - .6030

-

-

M16 x 2.0

.6299

16. mm

-

-

-

-

.5446 - .5594

.5906 - .6004

M16 x 1.5

.6299

16.0mm

-

-

-

-

.5659 - .5778

.5964 - .5239

3/4 - 10

.7500

-

.6450 - .6545

.6420 - .6630

.6526 - .6646

.7000 - .7090

-

-

3/4 - 16

.7500

-

.6820 - .6908

.6820 - .6960

.6892 - .6977

.7200 - .7260

-

-

M20 x 2.5

.7874

20.0mm

-

-

-

-

.6808 - .6985

.7382 - .7505

M20 x 1.5

.7874

20.0mm

-

-

-

-

.7234 - .7352

.7539 - .7601

7/8 - 9

.8750

-

.7550 - .7681

.7550 - .7780

.7668 - .7801

.8180 - .8290

-

-

7/8 - 14

.8750

-

.7980 - .8068

.7980 - .8140

.8055 - .8152

.8390 - .8450

-

-

M24 x 3.0

.9448

24.0mm

-

-

-

-

.8170 - .8366

.8858 - .9006

M24 x 2.0

.9448

24.0mm

-

-

-

-

.8596 - .8744

-

1" - 8

1.0000

-

.8650 - .8797

.8650 - .8900

.8783 - .8933

.9350 - .9480

-

-

1" - 12

1.0000

-

.9100 - .9198

.9100 - .9280

.9189 - .9298

.9590 - .9670

-

-


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