The minimum length of thread engagement should be equal to twice the diameter of the screw. The hole diameter, to ensure optimum preformance, should provide for 65% to 75% thread engagement.

1.91

1.83

1.81

1.73

1.81

4.00

3.32

1.04

.081

.078

.077

.074

.077

.172

.197

.046

2.39

2.31

2.28

2.20

2.28

5.00

4.15

0.55

.093

.090

.088

.085

.088

.198

.208

.054

2.90

2.82

2.76

2.68

2.76

6.00

4.98

0.61

.118

.115

.112

.109

.112

.250

.232

.065

3.31

3.23

3.21

3.13

3.21

7.00

5.81

0.74

.128

.125

.122

.119

.122

.276

.242

.081

3.82

3.74

3.64

3.56

3.64

8.0

6.64

0.86

.155

.152

.148

.145

.148

.328

.272

.081

4.31

4.23

4.11

4.03

4.11

9.00

7.47

0.92

.177

.174

.168

.165

.168

.380

.315

.108

.182

.179

.174

.171

.174

.380

.315

.081

4.8

4.72

4.58

4.50

4.58

10.00

8.30

.098

.203

.200

.194

.191

.194

.432

.359

.108

5.75

5.66

5.48

5.40

5.48

12.00

9.96

1.23

6.05

5.97

5.78

5.70

5.78

13.00

10.46

1.23

.235

.232

.224

.221

.224

.500

.415

.130

6.78

6.70

6.48

6.40

6.48

14.00

11.62

1.23

.267

.294

.284

.281

.284

.625

.519

.144

7.69

7.61

7.32

7.27

7.35

16.00

13.28

1.53

.359

.356

.343

.340

.343

.750

.623

.162

9.64

9.56

9.22

9.14

9.22

20.00

16.60

1.84

.419

.416

.400

.397

.400

.875

.726

.186

11.59

11.51

11.09

11.01

11.09

24.00

19.92

2.15

.481

.478

.460

.457

.460

1.00

.830

.200