The dimensions listed below can be used to determine the diameter along with the thread pitch. For further clarification of thread per inch, please download our gauge guide.
External Thread Dimensions
Major Dia. | Pitch Dia. | Minor Dia. | |||||||
Designation | Size Decimal | TPI | Tol. Class | Max | Min | Max | Min | Max | Min |
3/8-12 Acme | 0.375 | 12 | 2G | 0.375 | 0.37 | 0.3284 | 0.3161 | 0.2817 | 0.2632 |
1/2-10 Acme | 0.5 | 10 | 2G | 0.5 | 0.495 | 0.4443 | 0.4306 | 0.38 | 0.3594 |
5/8- 4 Acme | 0.625 | 4 | 2G STUB | 0.625 | 0.619 | 0.5421 | 0.524 | 0.455 | 0.4327 |
5/8-6 Acme | 0.625 | 6 | 2G | 0.625 | 0.6167 | 0.5348 | 0.5174 | 0.4383 | 0.4128 |
5/8-8 Acme | 0.625 | 8 | 2G | 0.625 | 0.6188 | 0.5562 | 0.5408 | 0.48 | 0.457 |
5/8- 10 Acme | 0.625 | 10 | 2G | 0.625 | 0.62 | 0.5693 | 0.5556 | 0.505 | 0.4844 |
3/4-5 Acme | 0.75 | 5 | 2G | 0.75 | 0.74 | 0.642 | 0.6226 | 0.53 | 0.5009 |
3/4-6 Acme | 0.75 | 6 | 2G | 0.75 | 0.7417 | 0.6598 | 0.6424 | 0.5633 | 0.5371 |
3/4-8 Acme | 0.75 | 8 | 2G | 0.75 | 0.7438 | 0.6812 | 0.6658 | 0.605 | 0.582 |
3/4-10 Acme | 0.75 | 10 | 2G | 0.75 | 0.745 | 0.6931 | 0.6784 | 0.63 | 0.608 |
7/8-5 Acme | 0.875 | 5 | 2G | 0.875 | 0.865 | 0.767 | 0.7476 | 0.655 | 0.6259 |
7/8-6 Acme | 0.875 | 6 | 2G | 0.875 | 0.8667 | 0.7842 | 0.7663 | 0.6883 | 0.6615 |
7/8-8 Acme | 0.875 | 7 | 2G | 0.875 | 0.8688 | 0.8062 | 0.7908 | 0.73 | 0.707 |
1-4 Acme | 0.875 | 4 | 2G | 1 | 0.9875 | 0.8652 | 0.8429 | 0.73 | 0.6965 |
1-5 Acme | 1 | 5 | 2G | 1 | 0.99 | 0.892 | 0.8726 | 0.78 | 0.7509 |
1-6 Acme | 1 | 6 | 2G | 1 | 0.9917 | 0.9098 | 0.8929 | 0.8133 | 0.7871 |
1-8 Acme | 1 | 8 | 2G | 1 | 0.9938 | 0.9312 | 0.9158 | 0.855 | 0.832 |
1-10Acme | 1 | 10 | 2G | 1 | 0.995 | 0.942 | 0.9264 | 0.88 | 0.8568 |
1 1/8-4 Acme | 1.125 | 4 | 2G | 1.125 | 1.1125 | 0.9902 | 0.9679 | 0.855 | 0.8219 |
1 1/8-5 Acme | 1.125 | 5 | 2G | 1.125 | 1.115 | 1.0165 | 0.9967 | 0.905 | 0.8753 |
1 1/8-6 Acme | 1.125 | 6 | 2G | 1.125 | 1.1167 | 1.0312 | 1.0163 | 0.9383 | 0.9115 |
1 1/4-4 Acme | 1.25 | 4 | 2G | 1.25 | 1.2375 | 1.1152 | 1.0929 | 0.98 | 0.9465 |
1 1/4-5 Acme | 1.25 | 5 | 2G | 1.25 | 1.24 | 1.1411 | 1.121 | 1.03 | 0.9998 |
1 1/4-6 Acme | 1.25 | 6 | 2G | 1.25 | 1.2417 | 1.1598 | 1.1424 | 1.0633 | 1.0371 |
1 1/4-8 Acme | 1.25 | 8 | 2G | 1.25 | 1.2437 | 1.1786 | 1.1612 | 1.105 | 1.079 |
1 3/8-4 Acme | 1.375 | 4 | 2G | 1.375 | 1.3625 | 1.2406 | 1.2186 | 1.105 | 1.0719 |
1 3/8-5 Acme | 1.375 | 5 | 2G | 1.375 | 1.365 | 1.2661 | 1.2461 | 1.155 | 1.124 |
1 3/8-6 Acme | 1.375 | 6 | 2G | 1.375 | 1.3667 | 1.2848 | 1.2674 | 1.1883 | 1.1621 |
1 1/2-4 Acme | 1.5 | 4 | 2G | 1.5 | 1.4875 | 1.3652 | 1.3429 | 1.23 | 1.1965 |
1 1/2-5 Acme | 1.5 | 5 | 2G | 1.5 | 1.49 | 1.392 | 1.3726 | 1.28 | 1.2209 |
1 1/2-6Acme | 1.5 | 6 | 2G | 1.5 | 1.4834 | 1.4098 | 1.3924 | 1.3133 | 1.2871 |
1 3/4-4 Acme | 1.75 | 4 | 2G | 1.75 | 1.7375 | 1.6145 | 1.5916 | 1.48 | 1.4456 |
1 3/4-5 Acme | 1.75 | 5 | 2G | 1.75 | 1.74 | 1.642 | 1.6226 | 1.53 | 1.5009 |
1 3/4-6 Acme | 1.75 | 6 | 2G | 1.75 | 1.7417 | 1.6561 | 1.6359 | 1.5633 | 1.5331 |
2-4 Acme | 2 | 4 | 2G | 2 | 1.9875 | 1.8637 | 1.8402 | 1.73 | 1.6948 |
2 1/4 - 4 Acme | 2.25 | 4 | 2G | 2.25 | 2.2375 | 2.1137 | 2.0902 | 1.98 | 1.9448 |
2 1/2 -4 Acme | 2.5 | 4 | 2G | 2.5 | 2.4875 | 2.3637 | 2.3402 | 2.23 | 2.1948 |
Internal Thread Dimensions
Major Dia. | Pitch Dia. | Minor Dia. | |||||||
Designation | Size Decimal | TPI | Tol. Class | Max | Min | Max | Min | Max | Min |
3/8-12 Acme | 0.375 | 12 | 2G | 0.375 | 0.385 | 0.3457 | 0.3333 | 0.2967 | 0.2917 |
1/2-10 Acme | 0.5 | 10 | 2G | 0.54 | 0.52 | 0.4637 | 0.45 | 0.405 | 0.4 |
5/8- 4 Acme | 0.625 | 4 | 2G STUB | 0.6647 | 0.645 | 0.5697 | 0.55 | 0.4875 | 0.475 |
5/8-6 Acme | 0.625 | 6 | 2G | 0.665 | 0.645 | 0.5587 | 0.5417 | 0.4667 | 0.4583 |
5/8-8 Acme | 0.625 | 8 | 2G | 0.665 | 0.645 | 0.5779 | 0.5625 | 0.5062 | 0.5 |
3/4-5 Acme | 0.75 | 5 | 2G | 0.79 | 0.77 | 0.6686 | 0.65 | 0.56 | 0.55 |
3/4-6 Acme | 0.75 | 6 | 2G | 0.79 | 0.77 | 0.6841 | 0.6667 | 0.5717 | 0.5833 |
3/4-8 Acme | 0.75 | 8 | 2G | 0.79 | 0.77 | 0.7033 | 0.6875 | 0.6312 | 0.625 |
3/4-10 Acme | 0.75 | 10 | 2G | 0.79 | 0.77 | 0.7147 | 0.7 | 0.655 | 0.65 |
7/8-5 Acme | 0.875 | 5 | 2G | 0.915 | 0.895 | 0.794 | 0.775 | 0.685 | 0.675 |
7/8-6 Acme | 0.875 | 6 | 2G | 0.915 | 0.895 | 0.8095 | 0.7917 | 0.7167 | 0.7083 |
7/8-8 Acme | 0.875 | 8 | 2G | 0.915 | 0.895 | 0.8287 | 0.8125 | 0.7562 | 0.75 |
1-4 Acme | 0.875 | 4 | 2G | 1.04 | 1.02 | 0.896 | 0.875 | 0.7625 | 0.75 |
1-5 Acme | 1 | 5 | 2G | 1.04 | 1.02 | 0.9194 | 0.9 | 0.81 | 0.8 |
1-6 Acme | 1 | 6 | 2G | 1.04 | 1.02 | 0.9349 | 0.9167 | 0.8417 | 0.8333 |
1-8 Acme | 1 | 8 | 2G | 1.04 | 1.02 | 0.9541 | 0.9375 | 0.8812 | 0.875 |
1-10 Acme | 1 | 10 | 2G | 1.04 | 1.02 | 0.9655 | 0.95 | 0.905 | 0.9 |
1 1/8-4 Acme | 1.125 | 4 | 2G | 1.165 | 1.145 | 1.0214 | 1 | 0.8875 | 0.875 |
1 1/8-5 Acme | 1.125 | 5 | 2G | 1.165 | 1.145 | 1.0488 | 1.025 | 0.935 | 0.925 |
1 1/8-6 Acme | 1.125 | 6 | 2G | 1.165 | 1.145 | 1.0603 | 1.0417 | 0.09667 | 0.9583 |
1 1/4-4 Acme | 1.25 | 4 | 2G | 1.29 | 1.27 | 1.1467 | 1.125 | 1.0125 | 1 |
1 1/4-5 Acme | 1.25 | 5 | 2G | 1.29 | 1.27 | 1.1701 | 1.15 | 1.06 | 1.05 |
1 1/4-6 Acme | 1.25 | 6 | 2G | 1.29 | 1.27 | 1.1856 | 1.1667 | 1.0917 | 1.0833 |
1 3/8-4 Acme | 1.375 | 4 | 2G | 1.415 | 1.395 | 1.272 | 1.25 | 1.375 | 1.125 |
1 3/8-5 Acme | 1.375 | 5 | 2G | 1.415 | 1.395 | 1.2955 | 1.275 | 1.185 | 1.175 |
1 3/8-6 Acme | 1.375 | 6 | 2G | 1.415 | 1.395 | 1.3109 | 1.2917 | 1.2167 | 1.2083 |
1 1/2-4 Acme | 1.5 | 4 | 2G | 1.54 | 1.52 | 1.3973 | 1.375 | 1.2625 | 1.25 |
1 1/2-5 Acme | 1.5 | 5 | 2G | 1.54 | 1.52 | 1.4208 | 1.4 | 1.31 | 1.3 |
1 1/2-6Acme | 1.5 | 6 | 2G | 1.54 | 1.52 | 1.4363 | 1.4167 | 1.3417 | 1.333 |
1 3/4-4 Acme | 1.75 | 4 | 2G | 1.79 | 1.77 | 1.6479 | 1.625 | 1.5125 | 1.5 |
1 3/4-5 Acme | 1.75 | 5 | 2G | 1.79 | 1.77 | 1.6714 | 1.65 | 1.56 | 1.55 |
1 3/4-6 Acme | 1.75 | 6 | 2G | 1.79 | 1.77 | 1.6869 | 1.6667 | 1.5917 | 1.5833 |
2-4 Acme | 2 | 4 | 2G | 2.04 | 2.02 | 1.8985 | 1.875 | 1.7625 | 1.75 |
2 1/4 - 4 Acme | 2.25 | 4 | 2G | 2.2906 | 2.27 | 2.149 | 2.0125 | 2.125 | 2 |
2 1/2 -4 Acme | 2.5 | 4 | 2G | 2.54 | 2.52 | 2.3995 | 2.375 | 2.2625 | 2.25 |