8UN and 8UNR Fixed Pitch Series Thread Chart

Measured in Inches
Size Primary
Inch
Basic Major Diameter
Inch
Basic Pitch Diameter
Inch
Minor Diameter, inch Minor Dia. Area
sq. inch
Tensile Stress Area
sq. inch
External Thread Internal Thread
1 1 0.9188 0.8512 0.8647 0.551 0.606
1 - 1/6 1.0625 0.9813 0.9137 0.9272 0.636 0.695
1 - 1/8 1.125 1.0438 0.9792 0.9897 0.728 0.79
1 - 3/16 1.1875 1.1063 1.0387 1.0522 0.825 0.892
1 - 1/4 1.25 1.1688 1.1012 1.1147 0.929 1
1 - 5/16 1.3125 1.2313 1.1637 1.1772 1.039 1.114
1 - 3/8 1.375 1.2938 1.2262 1.2397 1.155 1.233
1 - 7/16 1.4375 1.3563 1.2887 1.3022 1.277 1.36
1 - 1/2 1.5 1.4188 1.3512 1.3647 1.405 1.492
1 - 9/16 1.5625 1.4813 1.4137 1.4272 1.54 1.63
1 - 5/8 1.625 1.5438 1.4806 1.4897 1.68 1.78
1 - 11/16 1.6875 1.6063 1.5387 1.5522 1.83 1.93
1 - 3/4 1.75 1.6688 1.6012 1.6147 1.98 2.08
1 - 13/16 1.8125 1.7313 1.6637 1.6772 2.14 2.25
1 - 7/8 1.875 1.7938 1.7262 1.7397 2.3 2.41
1 - 15/16 1.9375 1.8563 1.7887 1.8022 2.47 2.59
2 2 1.9188 1.8512 1.8647 2.65 2.77
2 - 1/8 2.125 2.0438 1.9762 1.9897 3.03 3.15
2 - 1/4 2.25 2.1688 2.1012 2.1147 3.42 3.56
2 - 3/8 2.375 2.2938 2.2262 2.2397 3.85 3.99
2 - 1/2 2.5 2.4188 2.3512 2.3647 4.29 4.44
2 - 5/8 2.625 2.5438 2.4762 2.4897 4.76 4.92
2 - 3/4 2.75 2.6688 2.6012 2.6147 5.26 5.43
2 - 7/8 2.875 2.7938 2.7262 2.7397 5.78 5.95
3 3 2.9188 2.8512 2.8647 6.32 6.51
3 - 1/8 3.125 3.0438 2.9762 2.9897 6.89 7.08
3 - 1/4 3.25 3.1688 3.1012 3.1147 7.49 7.69
3 - 3/8 3.375 3.2938 3.2262 3.2397 8.11 8.31
3 - 1/2 3.5 3.4188 3.3512 3.3647 8.75 8.96
3 - 5/8 3.625 3.5438 3.4762 3.4897 9.42 9.64
3 - 3/4 3.75 3.6688 3.6012 3.6147 10.11 10.34
3 - 7/8 3.875 3.7938 3.7262 3.7397 10.83 11.06
4 4 3.9188 3.8516 3.8647 11.57 11.81
4 - 1/8 4.125 4.0438 3.9762 3.9897 12.34 12.59
4 - 1/4 4.25 4.1688 4.1012 4.1147 13.12 13.38
4 - 3/8 4.375 4.2938 4.2262 4.2397 13.94 14.21
4 - 1/2 4.5 4.4188 4.3512 4.3647 14.78 15.1
4 - 5/8 4.625 4.5438 4.4762 4.4897 15.6 15.9
4 - 3/4 4.75 4.6688 4.6012 4.6147 16.5 16.8
4 - 7/8 4.875 4.7938 4.7262 4.7397 17.4 17.7
5 5 4.9188 4.8512 4.8647 18.4 18.7
5 - 1/8 5.125 5.0438 4.9762 4.9897 19.3 19.7
5 - 1/4 5.25 5.1688 5.1012 5.1147 20.3 20.7
5 - 3/8 5.375 5.2938 5.2262 5.2397 21.3 21.7
5 - 1/2 5.5 5.4188 5.3512 5.3647 22.4 22.7
5 - 5/8 5.625 5.5438 5.4762 5.4897 23.4 23.8
5 - 3/4 5.75 5.6688 5.6012 5.6147 24.5 24.9
5 - 7/8 5.875 5.7938 5.7262 5.7397 25.6 26
6 6 5.9188 5.8512 5.8647 26.8 27.1