Thread geometry - Unified Coarse (UNC)

 

All dimensions in mm unless otherwise stated.

 

d1 - Minor thread diameter male

d2 - Minor Thread diameter female

d3 - Pitch diameter

d4 - Major diameter
 
Thread Major diameter Thread per inch Pitch diameter Minor diameter male thread Minor diameter female thread
1 0.0730 64 0.0629 0.0544 0.0561
2 0.0860 56 0.0744 0.0648 0.0667
3 0.0990 48 0.0855 0.0741 0.0764
4 0.1120 40 0.0958 0.0822 0.0849
5 0.1250 40 0.1088 0.0952 0.0979
6 0.1380 32 0.1177 0.1008 0.1042
8 0.1640 32 0.1437 0.1268 0.1302
10 0.1900 24 0.1629 0.1404 0.1449
12 0.2160 24 0.1889 0.1664 0.1709
1/4 0.2500 20 0.2175 0.1905 0.1959
 
Thread Major diameter Thread per inch Pitch diameter Minor diameter male thread Minor diameter female thread
5/16 0.3125 18 0.2764 0.2464 0.2524
3/8 0.3750 16 0.3344 0.3005 0.3073
7/16 0.4375 14 0.3911 0.3525 0.3602
1/2 0.5000 13 0.4500 0.4084 0.4167
9/16 0.5625 12 0.5084 0.4633 0.4723
5/8 0.6250 11 0.5660 0.5168 0.5266
3/4 0.7500 10 0.6850 0.6309 0.6417
7/8 0.8750 9 0.8028 0.7427 0.7547
1 1.0000 8 0.9188 0.8512 0.8647
1-1/8 1.1250 7 1.0322 0.9549 0.9704
 
Thread Major diameter Thread per inch Pitch diameter Minor diameter male thread Minor diameter female thread
1 1/4 1.2500 7 1.1572 1.0799 1.0954
1-3/8 1.3750 6 1.2667 1.1766 1.1946
1 1/2 1.5000 6 1.3917 1.3016 1.3196
1 3/4 1.7500 5 1.6201 1.5119 1.5335
2 2.0000 4.5 1.8557 1.7353 1.7594
2 1/4 2.2500 4.5 2.1057 1.9853 2.0094
2 1/2 2.5000 4 2.3376 2.2023 2.2294
2 3/4 2.7500 4 2.5876 2.4523 2.4794
3 3.0000 4 2.8376 2.7023 2.7294
3 1/4 3.2500 4 3.0876 2.9523 2.9794
 
Thread Major diameter Thread per inch Pitch diameter Minor diameter male thread Minor diameter female thread
3 1/2 3.5000 4 3.3376 3.2023 3.2294
3 3/4 3.7500 4 3.5876 3.4523 3.4794
4 4.0000 4 3.8376 3.7023 3.7294