Diameter of screw.

Threadsper inch.

Diameter at root of thread.

Diameter of screw.

Threadsper inch.

Diameter at root of thread.

1/4

20

.185

2

4 1/2

1.7113

5/16

18

.2403

2 1/4

4 1/2

1.9613

3/8

16

.2936

2 1/2

4

2.1752

7/16

14

.3447

2 3/4

4

2.4252

1/2

13

.4001

3

3 1/2

2.6288

9/16

12

.4542

3 1/4

3 1/2

2.8788

5/8

11

.5069

3 1/2

3 1/4

3.1003

3/4

10

.6201

3 3/4

3

3.3170

7/8

9

.7307

4

3

3.5670

1

8

.8376

4 1/4

2 7/8

3.7982

1 1/8

7

.9394

4 1/2

2 3/4

4.0276

1 1/4

7

1.0644

4 3/4

2 5/8

4.2551

1 3/8

6

1.1585

5

2 1/2

4.4804

1 1/2

6

1.2835

5 1/4

2 1/2

4.7304

1 5/8

5 1/2

1.3888

5 1/2

2 3/8

4.9530

1 3/4

5

1.4902

5 3/4

2 3/8

5.2030

1 7/8

5

1.6152

6

2 1/4

5.4226