Nominal

Thread Size

Minor Diameter

(After Tapping)

Suggested Drill Size1

F Dim.2

Minimum Drilling Depth for Taps

Min. All

Classes

Max Class

3B

Max Class

2B

Aluminum

Steel Magnesium

Plastic

Plug Taps

1

11/2

2

21/2

3

Unified Coarse

2 (.086)-56

3 (.099)-48

4 (.112)-40

.0899

.1036

.1175

.0961

.1104

.1252

.0961

.1104

.1252

3/32 (.0938)

#36 (.1065)

#31 (.1200)

#41 (.0960)

7/64 (.1094)

#31 (.1200)

.236

.273

.318

.279

.323

.374

.322

.372

.430

.365

.422

.486

.408

.471

.542

5 (.125)-40

6 (.138)-32

8 (.164)-32

.1305

.1448

.1708

.1373

.1527

.1781

.1373

.1527

.1781

3.4mm (.1339)

#26 (.1470)

#17 (.1730)

#29 (.1360)

#25 (.1495)

#16 (.1770)

.338

.394

.434

.400

.464

.516

.462

.532

.598

.525

.602

.680

.588

.670

.762

10 (.190)-24

12 (.216)-24

1/ 4(.250)-20

.1990

.2250

.2608

.2080

.2340

.2704

.2087

.2347

.2723

13/64 (.2031)

#1 (.2280) H (.2660)

#5 (.2055)

#1 (.2280) H (.2660)

.535

.574

.675

.630

.682

.800

.725

.790

.925

.820

.898

1.050

.915

1.006

1.175

5/16 (.3125)-18

3/8 (.3750)-16

7/16 (.4375)-14

1/2 (.5000)-13*

.3245

.3885

.4530

.5166

.3342

.3987

.4639

.5273

.3372

.4026

.4688

.5335

Q (.3320)

X (.3970)

29/64 (.4531)

33/64 (.5156)

Q (.3320)

X (.3970)

29/64 (.4531)

17/32 (.5312)

.801

.750

.867

.962

.957

.938

1.086

1.212

1.113

1.125

1.305

1.462

1.269

1.312

1.524

1.712

1.425

1.500

1.743

1.962

9/16 (.5625)-12*

5/8 (.6250)-11

3/4 (.7500)-10

7/8 (.8750)- 9

1 (1.0000)- 8

.5806

.6447

.7716

.8990

1.0271

.5918

.6564

.7838

.9119

1.0421

.5986

.6641

.7926

.9213

1.0521

37/64 (.5781)

21/32 (.6562)

25/32 (.7812)

29/32 (.9062)

1-1/32 (1.0312)

19/32 (.5938)

21/32 (.6562)

25/32 (.7812)

29/32 (.9062)

1-1/32 (1.0312)

1.062

1.170

1.350

1.542

1.750

1.343

1.483

1.725

1.979

2.250

1.624

1.795

2.100

2.417

2.750

1.905

2.108

2.475

2.854

3.250

2.186

2.420

2.850

3.292

3.750

1- 1/8 (1.1250)- 7

1- 1/4 (1.2500)- 7

1- 3/8 (1.3750)- 6

1- 1/2 (1.5000)- 6

1.1559

1.2809

1.4110

1.5360

1.1730

1.2980

1.4310

1.5560

1.1834

1.3084

1.4416

1.5665

1-11/64 (1.1719)

1-19/64 (1.2969)

1-27/64 (1.4219)

1-35/64 (1.5469)

1-11/64 (1.1719)

1-19/64 (1.2969)

1-27/64 (1.4219)

1-35/64 (1.5469)

1.982

2.107

2.375

2.500

2.545

2.732

3.062

3.250

3.107

3.357

3.750

4.000

3.670

3.982

4.437

4.750

4.232

4.607

5.125

5.500

Unified Fine

3 (.099)-56

4 (.112)-48

6 (.138)-40

8 (.164)-36

10 (.190)-32

.1029

.1166

.1435

.1701

.1968

.1086

.1229

.1503

.1771

.2041

.1086

.1229

.1503

.1771

.2041

#37 (.1040)

3mm (.1181)

#26 (.1470)

#17 (.1730)

#7 (.2010)

#36 (.1065)

#31 (.1200)

#25 (.1495)

#16 (.1770)

13/64 (.2031)

.256

.293

.357

.413

.472

.305

.349

.426

.495

.568

.355

.405

.495

.577

.662

.404

.461

.564

.659

.758

.454

.517

.633

.741

.852

1/4 (.2500)-28

5/16 (.3125)-24

3/8 (.3750)-24

7/16 (.4375)-20

1/2 (.5000)-20

.2577

.3215

.3840

.4483

.5108

.2646

.3288

.3910

.4561

.5186

.2661

.3312

.3937

.4593

.5223

G (.2610)

21/64 (.3281)

25/64 (.3906)

29/64 (.4531)

33/64 (.5156)

6.7mm (.2638)

21/64 (.3281)

25/64 (.3906)

29/64 (.4531)

33/64 (.5156)

.589

.718

.625

.738

.800

.714

.874

.812

.957

1.050

.839

1.030

1.000

1.176

1.300

.964

1.186

1.187

1.395

1.550

1.089

1.342

1.375

1.614

1.800

9/16 (.5625)-18

5/8 (.6250)-18

3/4 (.7500)-16

7/8 (.8750)-14

1 (1.0000)-121

.5745

.6370

.7635

.8905

1.0181

.5826

.6451

.7720

.8994

1.0281

.5872

.6497

.7776

.9063

1.0361

37/64 (.5781)

41/64 (.6406)

49/64 (.7656)

57/64 (.8906)

1-1/64 (1.0156)

37/64 (.5781)

41/64 (.6406)

49/64 (.7655)

57/64 (.8906)

1-1/32 (1.0312)

.895

.958

1.125

1.304

1.500

1.176

1.271

1.500

1.741

2.000

1.457

1.583

1.875

2.179

2.500

1.738

1.896

2.250

2.616

3.000

2.019

2.208

2.625

3.054

3.500

1-1/8 (1.1250)-121

1-1/4 (1.2500)-121

1-3/8 (1.3750)-121

1-1/2 (1.5000)-121

1.1431

1.2681

1.3931

1.5181

1.1531

1.2781

1.4031

1.5281

1.1611

1.2861

1.4111

1.5361

1-9/64 (1.1406)

1-17/64 (1.2656)

1-25/64 (1.3906)

1-33/64 (1.5156)

1-5/32 (1.1562)

1-9/32 (1.2812)

1-13/32 (1.4062)

1-17/32 (1.5312)

1.625

1.750

1.875

2.000

2.187

2.375

2.562

2.750

2.750

3.000

3.250

3.500

3.312

3.625

3.937

4.250

3.875

4.250

4.625

5.000