Size Major Dia Threads Per Inch Pitch Dia Minor Dia Externala Minor Dia Internalb Minor Dia Area Tensile Stress Area
# inch tpi inch inch inch sq. inch sq. inch
c(0.216) 0.2160 32 0.1957 0.1788 0.1822 0.0242 0.0270
1/4 0.2500 32 0.2297 0.2128 0.2162 0.0344 0.0379
5/16 0.3125 32 0.2922 0.2753 0.2787 0.0581 0.0625
3/8 0.3750 32 0.3547 0.3378 0.3412 0.0878 0.0932
7/16 0.4375 28 0.4143 0.3949 0.3988 0.1201 0.1274
1/2 0.5000 28 0.4768 0.4574 0.4613 0.1620 0.1700
9/16 0.5625 24 0.5354 0.5129 0.5174 0.2030 0.2140
5/8 0.6250 24 0.5979 0.5754 0.5799 0.2560 0.2680
11/16c 0.6875 24 0.6604 0.6379 0.6424 0.3150 0.3290
3/4 0.7500 20 0.7175 0.6905 0.6959 0.3690 0.3860
13/16c 0.8125 20 0.7800 0.7530 0.7584 0.4390 0.4580
7/8 0.8750 20 0.8425 0.8155 0.8209 0.5150 0.5360
15/16c 0.9375 20 0.9050 0.8780 0.8834 0.5980 0.6200
1 1.0000 20 0.9675 0.9405 0.9459 0.6870 0.7110
11/16c 1.0625 18 1.0264 0.9964 1.0024 0.7700 0.7990
11/8 1.1250 18 1.0889 1.0589 1.0649 0.8710 0.9010
13/16c 1.1875 18 1.1514 1.1214 1.1274 0.9770 1.0090
11/4 1.2500 18 1.2139 1.1839 1.1899 1.0900 1.1230
15/16c 1.3125 18 1.2764 1.2464 1.2524 1.2080 1.2440
13/8 1.3750 18 1.3389 1.3089 1.3149 1.3330 1.3700
17/16c 1.4375 18 1.4014 1.3714 1.3774 1.4640 1.5030
11/2 1.5000 18 1.4639 1.4339 1.4399 1.6000 1.6400
19/16c 1.5625 18 1.5264 1.4964 1.5024 1.7400 1.7900
15/8 1.6250 18 1.5889 1.5589 1.5649 1.8900 1.9400
111/16c 1.6875 18 1.6514 1.6214 1.6274 2.0500 2.1000
Note:

a : Form for UNR thread
b : Basic Minor Diameter
c : Secondary Size