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UNF - 60 Degree Unified National Fine Threads

UNF Thread Series / UNRF, is suitable for the production of bolts, screws, and nuts and for other applications where the Coarse series is not applicable. External threads of this series have greater tensile stress area than comparable sizes of the Coarse series. The Fine series is suitable when the resistance to stripping of both external

#0 - #12 5/16" - 3/4" 7/8" - 1 1/2"

UNF Threads

Nominal Size External (b) Internal (b)
Threads per Inch and Series Designation Class Allowance Major Diameter Minor Diameter UNR Minor Dia.,c Max (Ref.) Class Minor Diameter Pitch Diameter Major Diameter
Max (d) Min Min (e) Max (d) Min Min Max Min Max Min
#0 - 80UNF 2A 0.0005 1.511 1.43 . . . 1.306 1.26 1.133 2B 1.181 1.306 1.318 1.377 1.524
#0 - 80UNF 3A 0 1.524 1.443 . . . 1.318 1.285 1.146 3B 1.181 1.306 1.318 1.361 1.524
#1 - 72UNF 2A 0.0006 1.839 1.75 . . . 1.61 1.562 1.42 2B 1.473 1.613 1.626 1.689 1.854
#1 - 72UNF 3A 0 1.854 1.765 . . . 1.626 1.59 1.435 3B 1.473 1.613 1.626 1.674 1.854
#2 - 64UNF 2A 0.0006 2.169 2.073 . . . 1.913 1.862 1.697 2B 1.755 1.913 1.928 1.996 2.184
#2 - 64UNF 3A 0 2.184 2.088 . . . 1.928 1.89 1.712 3B 1.755 1.913 1.928 1.979 2.184
#3 - 56UNF 2A 0.0007 2.497 2.393 . . . 2.202 2.146 1.958 2B 2.024 2.197 2.22 2.291 2.515
#3 - 56UNF 3A 0 2.515 2.41 . . . 2.22 2.179 1.976 3B 2.024 2.197 2.22 2.273 2.515
#4 - 48UNF 2A 0.0007 2.827 2.713 . . . 2.484 2.423 2.195 2B 2.271 2.459 2.502 2.581 2.845
#4 - 48UNF 3A 0 2.845 2.731 . . . 2.502 2.456 2.212 3B 2.271 2.459 2.502 2.56 2.845
#5 - 44UNF 2A 0.0007 3.157 3.035 . . . 2.781 2.718 2.469 2B 2.55 2.741 2.799 2.88 3.175
#5 - 44UNF 3A 0 3.175 3.053 . . . 2.799 2.751 2.487 3B 2.55 2.741 2.799 2.86 3.175
#6 - 40UNF 2A 0.0008 3.485 3.355 . . . 3.073 3.007 2.728 2B 2.819 3.023 3.094 3.18 3.505
#6 - 40UNF 3A 0 3.505 3.376 . . . 3.094 3.043 2.748 3B 2.819 3.012 3.094 3.157 3.505
#8 - 36UNF 2A 0.0008 4.145 4.006 . . . 3.688 3.617 3.305 2B 3.404 3.607 3.708 3.8 4.166
#8 - 36UNF 3A 0 4.166 4.026 . . . 3.708 3.655 3.325 3B 3.404 3.597 3.708 3.777 4.166
#10 - 32UNF 2A 0.0009 4.803 4.651 . . . 4.288 4.211 3.858 2B 3.962 4.166 4.31 4.409 4.826
#10 - 32UNF 3A 0 4.826 4.674 . . . 4.31 4.252 3.881 3B 3.962 4.168 4.31 4.384 4.826
#12 - 28UNF 2A 0.001 5.461 5.296 . . . 4.872 4.79 4.379 2B 4.496 4.724 4.897 5.004 5.486
#12 - 28UNF 3A 0 5.486 5.321 . . . 4.897 4.836 4.404 3B 4.496 4.717 4.897 4.976 5.486
5/16" - 24UNF 1A 0.0011 7.91 7.635 . . . 7.221 7.082 6.65 1B 6.782 7.036 7.249 7.43 7.938
5/16" - 24UNF 2A 0.0011 7.91 7.727 . . . 7.221 7.127 6.65 2B 6.782 7.036 7.249 7.371 7.938
5/16" - 24UNF 3A 0 7.938 7.755 . . . 7.249 7.181 6.678 3B 6.782 6.995 7.249 7.341 7.938
3/8" - 24UNF 1A 0.0011 9.497 9.223 . . . 8.809 8.664 8.237 1B 8.382 8.636 8.837 9.025 9.525
3/8" - 24UNF 2A 0.0011 9.497 9.314 . . . 8.809 8.712 8.237 2B 8.382 8.636 8.837 8.961 9.525
3/8" - 24UNF 3A 0 9.525 9.342 . . . 8.837 8.763 8.265 3B 8.382 8.565 8.837 8.931 9.525
7/16" - 20UNF 1A 0.0013 11.079 10.77 . . . 10.254 10.097 9.568 1B 9.728 10.033 10.287 10.493 11.113
7/16" - 20UNF 2A 0.0013 11.079 10.874 . . . 10.254 10.147 9.568 2B 9.728 10.033 10.287 10.424 11.113
7/16" - 20UNF 3A 0 11.113 10.907 . . . 10.287 10.208 9.601 3B 9.728 9.947 10.287 10.391 11.113
1/2" - 20UNF 1A 0.0013 12.667 12.357 . . . 11.841 11.679 11.156 1B 11.328 11.608 11.875 12.088 12.7
1/2" - 20UNF 2A 0.0013 12.667 12.461 . . . 11.841 11.732 11.156 2B 11.328 11.608 11.875 12.017 12.7
1/2" - 20UNF 3A 0 12.7 12.494 . . . 11.875 11.793 11.189 3B 11.328 11.524 11.875 11.981 12.7
9/16" - 18UNF 1A 0.0014 14.252 13.919 . . . 13.335 13.162 12.573 1B 12.751 13.081 13.371 13.597 14.288
9/16" -18UNF 2A 0.0014 14.252 14.031 . . . 13.335 13.221 12.573 2B 12.751 13.081 13.371 13.52 14.288
9/16" - 18UNF 3A 0 14.288 14.067 . . . 13.371 13.284 12.609 3B 12.751 12.969 13.371 13.482 14.288
5/8" - 18UNF 1A 0.0014 15.839 15.507 . . . 14.923 14.745 14.161 1B 14.351 14.681 14.958 15.189 15.875
5/8" - 18UNF 2A 0.0014 15.839 15.618 . . . 14.923 14.803 14.161 2B 14.351 14.681 14.958 15.11 15.875
5/8" - 18UNF 3A 0 15.875 15.654 . . . 14.958 14.869 14.196 3B 14.351 14.554 14.958 15.072 15.875
3/4" - 16UNF 1A 0.0015 19.012 18.651 . . . 17.981 17.79 17.12 1B 17.323 17.678 18.019 18.268 19.05
3/4" - 16UNF 2A 0.0015 19.012 18.773 . . . 17.981 17.854 17.12 2B 17.323 17.678 18.019 18.184 19.05
3/4" - 16UNF 3A 0 19.05 18.811 . . . 18.019 17.922 17.158 3B 17.323 17.546 18.019 18.143 19.05
7/8" - 14UNF 1A 0.0016 22.184 21.791 . . . 21.006 20.8 20.025 1B 20.269 20.676 21.046 21.316 22.225
7/8" - 14UNF 2A 0.0016 22.184 21.923 . . . 21.006 20.869 20.025 2B 20.269 20.676 21.046 21.224 22.225
7/8" - 14UNF 3A 0 22.225 21.963 . . . 21.046 20.942 20.066 3B 20.269 20.493 21.046 21.181 22.225
1" - 12UNF 1A 0.0018 25.354 24.917 . . . 23.98 23.757 22.835 1B 23.114 23.571 24.026 24.315 25.4
1" - 12UNF 2A 0.0018 25.354 25.065 . . . 23.98 23.83 22.835 2B 23.114 23.571 24.026 24.219 25.4
1" - 12UNF 3A 0 25.4 25.11 . . . 24.026 23.914 22.88 3B 23.114 23.363 24.026 24.171 25.4
1 1/8" - 12UNF 1A 0.0018 28.529 28.092 . . . 27.155 26.927 26.01 1B 26.289 26.746 27.201 27.498 28.575
1 1/8" - 12UNF 2A 0.0018 28.529 28.24 . . . 27.155 27.003 26.01 2B 26.289 26.746 27.201 27.399 28.575
1 1/8" - 12UNF 3A 0 28.575 28.285 . . . 27.201 27.087 26.055 3B 26.289 26.538 27.201 27.351 28.575
1 1/4" - 12UNF 1A 0.0018 31.704 31.267 . . . 30.33 30.096 29.185 1B 29.464 29.921 30.376 30.681 31.75
1 1/4" - 12UNF 2A 0.0018 31.704 31.415 . . . 30.33 30.173 29.185 2B 29.464 29.921 30.376 30.579 31.75
1 1/4" - 12UNF 3A 0 31.75 31.46 . . . 30.376 30.259 29.23 3B 29.464 29.713 30.376 30.528 31.75
1 3/8" - 12UNF 1A 0.0019 34.877 34.44 . . . 33.503 33.264 32.357 1B 32.639 33.096 33.551 33.863 34.925
1 3/8" - 12UNF 2A 0.0019 34.877 34.587 . . . 33.503 33.343 32.357 2B 32.639 33.096 33.551 33.759 34.925
1 3/8" - 12UNF 3A 0 34.925 34.635 . . . 33.551 33.431 32.405 3B 32.639 32.888 33.551 33.706 34.925
1 1/2" - 12UNF 1A 0.0019 38.052 37.615 . . . 36.678 36.434 35.532 1B 35.814 36.271 36.726 37.043 38.1
1 1/2" - 12UNF 2A 0.0019 38.052 37.762 . . . 36.678 36.515 35.532 2B 35.814 36.271 36.726 36.937 38.1
1 1/2" - 12UNF 3A 0 38.1 37.81 . . . 36.726 36.604 35.58 3B 35.814 36.063 36.726 36.886 38.1