Basic

Basic Basic minor minor dia

effective dia of ext. of int.
NF/NC Threads Basic major dia threads threads Drill
Tap size UNF/UNC per inch dia (inches) (inches) (inches) (inches) size
0-80 UNF 80 .0600 .0519 .0447 .0465 3/64
1-64 UNC 64 .0730 .0629 .0538 .0561 #54
2-56 UNC 56 .0860 .0744 .0641 .0667 #50
2-64 UNF 64 .0860 .0759 .0668 .0691 #50
4-40 UNC 40 .1120 .0958 .0813 .0849 #43
4-48 UNF 48 .1120 .0985 .0864 .0894 #42
5-40 UNC 40 .1250 .1088 .0943 .0979 #38
5-44 UNF 44 .1250 .1102 .0971 .1004 #37
6-32 UNC 32 .1360 .1177 .0997 .1042 #36
6-40 UNF 40 .1360 .1218 .1073 .1109 #33
8-32 UNC 32 .1640 .1437 .1257 .1302 #29
8-36 UNF 36 .1640 .1460 .1299 .1339 #29
10-24 UNC 24 .1900 .1629 .1389 .1449 #25
10-32 UNF 32 .1900 .1697 .1517 .1562 #21
1/4-20 UNC 20 .2500 .2175 .1887 .1959 #7
1/4-28 UNF 28 .2500 .2268 .2062 .2113 #3
5/16-18 UNC 18 .3125 .2764 .2443 .2524 F
5/16-24 UNF 24 .3125 .2854 .2614 .2674 I
3/8-16 UNC 16 .3750 .3344 .2983 .3073 5/16
3/8-24 UNF 24 .3750 .3479 .3239 .3299 Q
7/16-14 UNC 14 .4375 .3911 .3499 .3602 U
7/16-20 UNF 20 .4375 .4050 .3762 .3834 25/64
1/2-13 UNC 13 .5000 .4500 .4056 .4167 27/64
1/2-20 UNF 20 .5000 .4675 .4387 .4459 29/64
9/16-12 UNC 12 .5625 .5084 .4603 .4723 31/64
9/16-18 UNF 18 .5625 .5264 .4943 .5024 33/64
5/8-11 UNC 11 .6250 .5660 .5135 .5266 17/32
5/8-18 UNF 18 .6250 .5869 .5568 .5649 37/64
3/4-10 UNC 10 .7500 .6650 .6273 .6417 21/32
3/4-16 UNF 16 .7500 .7094 .6733 .6823 11/16
7/8-9 UNC 9 .8750 .8028 .7387 .7547 49/64
7/8-14 UNF 14 .8750 .8286 .7874 .7977 13/16
1-8 UNC 8 1.000 .9188 .8466 .8647 7/8
1-14 UNF 14 1.000 .9459 .8978 .9098 15/16
1 1/8-7 UNC 7 1.1250 1.0322 .9497 .9704 63/64
1 1/8-12 UNF 12 1.1250 1.0709 1.0228 1.0348 1 3/64
1 1/4-7 UNC 7 1.2500 1.1572 1.0747 1.0954 1 7/64
1 3/8-6 UNC 6 1.3750 1.2667 1.1705 1.1946 1 13/64
1 1/2-6 UNC 6 1.5000 1.3917 1.2955 1.3196 1 11/32
1 3/4-5 UNC 5 1.7500 1.6201 1.5046 1.5335 1 35/64
2-4.5 UNC 4 1/2 2.0000 1.8557 1.7274 1.7594 1 25/32