Mechanical Engineering Drawing Workshop

UNC threadName of thread

Thread/inch

PitchDiameter

1st priority

2nd priorityNo. 1 - 64 UNC

64 0.3969

1.854

No. 2 - 56 UNC

56 0.4536

2.184

No. 3 - 48 UNC

48 0.5292

2.515

No. 4 - 40 UNC

40 0.6350

2.845

No. 5 - 40 UNC

40 0.6350

3.175

No. 6 - 32 UNC

32 0.7938

3.505

No. 8 - 32 UNC

32 0.7938

4.166

No. 10 - 24 UNC

24 1.0583

4.826

No. 12 - 24 UNC

24 1.0583

5.486

1/4- 20 UNC

20 1.2700

6.350

5/16- 18 UNC

18 1.4111

7.938

3/8- 16 UNC

16 1.5875

9.525

7/16- 14 UNC

14 1.8143

11.112

1/2- 13 UNC

13 1.9538

12.700

9/16- 12 UNC

12 2.1167

14.288

5/8- 11 UNC

11 2.3091

15.875

3/4- 10 UNC

10 2.5400

19.050

7/8- 9 UNC

9 2.8222

22.225