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Unified Screw Thread Forms

Threads per Inch n Pitch P Depth of Sharp V-Thread 0.86603P Depth of Int. Thd. and UN Ext. Thd.a 0.54127P Depth of UNR Ext. Thd. 0.59539P Truncation of Ext. Thd. Root 0.21651P Truncation of UNR Ext. Thd. Rootb 0.16238P Truncation of Ext. Thd. Crest 0.10825P Truncation of Int. Thd. Root 0.10825OP Truncation of Int. Thd.Crest 0.2165P Flat at Ext. Thd. Crest and Int. Thd. Root 0.125P Basic Flat at Int. Thd. Crestc 0.25P Maximum Ext. Thd. Root Radius .14434P Addendum of Ext. Thd 0.32476P
80 0.0125 0.01083 0.00677 0.00744 0.00271 0.00203 0.00135 0.00135 0.00271 0.00156 0.00312 0.0018 0.00406
72 0.01389 0.01203 0.00752 0.00827 0.00301 0.00226 0.0015 0.0015 0.00301 0.00174 0.00347 0.002 0.00451
64 0.01563 0.01353 0.00846 0.0093 0.00338 0.00254 0.00169 0.00169 0.00338 0.00195 0.00391 0.00226 0.00507
56 0.01786 0.01546 0.00967 0.01063 0.00387 0.0029 0.00193 0.00193 0.00387 0.00223 0.00446 0.00258 0.0058
48 0.02083 0.01804 0.01128 0.0124 0.00451 0.00338 0.00226 0.00226 0.00451 0.0026 0.00521 0.00301 0.00677
44 0.02273 0.01968 0.0123 0.01353 0.00492 0.00369 0.00246 0.00246 0.00492 0.00284 0.00568 0.00328 0.00738
40 0.025 0.02165 0.01353 0.01488 0.00541 0.00406 0.00271 0.00271 0.00541 0.00312 0.00625 0.00361 0.00812
36 0.02778 0.02406 0.01504 0.01654 0.00601 0.00451 0.00301 0.00301 0.00601 0.00347 0.00694 0.00401 0.00902
32 0.03125 0.02706 0.01691 0.01861 0.00677 0.00507 0.00338 0.00338 0.00677 0.00391 0.00781 0.00451 0.01015
28 0.03571 0.03093 0.01933 0.02126 0.00773 0.0058 0.00387 0.00387 0.00773 0.00446 0.00893 0.00515 0.0116
27 0.03704 0.03208 0.02005 0.02205 0.00802 0.00601 0.00401 0.00401 0.00802 0.00463 0.00926 0.00535 0.01203
24 0.04167 0.03608 0.02255 0.02481 0.00902 0.00677 0.00451 0.00451 0.00902 0.00521 0.01042 0.00601 0.01353
20 0.05 0.0433 0.02706 0.02977 0.01083 0.00812 0.00541 0.00541 0.01083 0.00625 0.0125 0.00722 0.01624
18 0.05556 0.04811 0.03007 0.03308 0.01203 0.00902 0.00601 0.00601 0.01203 0.00694 0.01389 0.00802 0.01804
16 0.0625 0.05413 0.03383 0.03721 0.01353 0.01015 0.00677 0.00677 0.01353 0.00781 0.01562 0.00902 0.0203
14 0.07143 0.06186 0.03866 0.04253 0.01546 0.0116 0.00773 0.00773 0.01546 0.00893 0.01786 0.01031 0.0232
13 0.07692 0.06662 0.04164 0.0458 0.01655 0.01249 0.00833 0.00833 0.01665 0.00962 0.01923 0.0111 0.02498
12 0.08333 0.07217 0.04511 0.04962 0.01804 0.01353 0.00902 0.00902 0.01804 0.01042 0.02083 0.01203 0.02706
11 1⁄2 0.08696 0.07531 0.04707 0.05177 0.01883 0.01412 0.00941 0.00941 0.01883 0.01087 0.02174 0.01255 0.02824
11 0.09091 0.07873 0.04921 0.05413 0.01968 0.01476 0.00984 0.00984 0.01968 0.01136 0.02273 0.01312 0.02952
10 0.1 0.0866 0.05413 0.05954 0.02165 0.01624 0.01083 0.01083 0.02165 0.0125 0.025 0.01443 0.03248
9 0.11111 0.09623 0.06014 0.06615 0.02406 0.01804 0.01203 0.01203 0.02406 0.01389 0.02778 0.01604 0.03608
8 0.125 0.10825 0.06766 0.07442 0.02706 0.0203 0.01353 0.01353 0.02706 0.01562 0.03125 0.01804 0.04059
7 0.14286 0.12372 0.07732 0.08506 0.03093 0.0232 0.01546 0.01546 0.03093 0.01786 0.03571 0.02062 0.04639
6 0.16667 0.14434 0.09021 0.09923 0.03608 0.02706 0.01804 0.01804 0.03608 0.02083 0.04167 0.02406 0.05413
5 0.2 0.17321 0.10825 0.11908 0.0433 0.03248 0.02165 0.02165 0.0433 0.025 0.05 0.02887 0.06495
41⁄2 0.22222 0.19245 0.12028 0.13231 0.04811 0.03608 0.02406 0.02406 0.04811 0.02778 0.05556 0.03208 0.07217
4 0.25 0.21651 0.13532 0.14885 0.05413 0.04059 0.02706 0.02706 0.05413 0.03125 0.0625 0.03608 0.08119
  • a Also depth of thread engagement.
  • b Design profile.
  • c Also basic flat at external UN thread root.
  • All dimensions are in inches.