6UN and 6UNR 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 - 3/8 1.375 1.2667 1.1766 1.1946 1.054 1.155
1 - 7/16 1.4375 1.3292 1.2391 1.2571 1.171 1.277
1 - 1/2 1.5 1.3917 1.3016 1.3196 1.294 1.405
1 - 9/16 1.5625 1.4542 1.3641 1.3821 1.423 1.54
1 - 5/8 1.625 1.5167 1.4271 1.4446 1.56 1.68
1 - 11/16 1.6875 1.5792 1.4891 1.5071 1.7 1.83
1 - 3/4 1.75 1.6417 1.5516 1.5696 1.85 1.98
1 - 13/16 1.8125 1.7042 1.6141 1.6321 2 2.14
1 - 7/8 1.875 1.7667 1.6766 1.6946 2.16 2.3
1 - 15/16 1.9375 1.8292 1.7391 1.7571 2.33 2.47
2 2 1.8917 1.8016 1.8196 2.5 2.65
2 - 1/8 2.125 2.0167 1.9266 1.9446 2.86 3.03
2 - 1/4 2.25 2.1417 2.0516 2.0696 3.25 3.42
2 - 3/8 2.375 2.2667 2.1766 2.1946 3.66 3.85
2 - 1/2 2.5 2.3917 2.3016 2.3196 4.1 4.29
2 - 5/8 2.625 2.5167 2.4266 2.4446 4.56 4.76
2 - 3/4 2.75 2.6417 2.5516 2.5696 5.04 5.26
2 - 7/8 2.875 2.7667 2.6766 2.6946 5.55 5.78
3 3 2.8917 2.8016 2.8196 6.09 6.33
3 - 1/8 3.125 3.0167 2.9266 2.9446 6.64 6.89
3 - 1/4 3.25 3.1417 3.0516 3.0696 7.23 7.49
3 - 3/8 3.375 3.2667 3.1766 3.1946 7.84 8.11
3 - 1/2 3.5 3.3917 3.3016 3.3196 8.47 8.75
3 - 5/8 3.625 3.5167 3.4266 3.4446 9.12 9.42
3 - 3/4 3.75 3.6417 3.5516 3.5696 9.81 10.11
3 - 7/8 3.875 3.7667 3.6766 3.6946 10.51 10.83
4 4 3.8917 3.8016 3.8196 11.24 11.57
4 - 1/8 4.125 4.0167 3.9266 3.9446 12 12.33
4 - 1/4 4.25 4.1417 4.0516 4.0696 12.78 13.12
4 - 3/8 4.375 4.2667 4.1766 4.1946 13.58 13.94
4 - 1/2 4.5 4.3917 4.3016 4.3196 14.41 14.78
4 - 5/8 4.625 4.5167 4.4266 4.4446 15.3 15.6
4 - 3/4 4.75 4.6417 4.5516 4.5696 16.1 16.5
4 - 7/8 4.875 4.7667 4.6766 4.6946 17 17.5
5 5 4.8917 4.8016 4.8196 18 18.4
5 - 1/8 5.125 5.0167 4.9266 4.9446 18.9 19.3
5 - 1/4 5.25 5.1417 5.0516 5.0696 19.9 20.3
5 - 3/8 5.375 5.2667 5.1766 5.1946 20.9 21.3
5 - 1/2 5.5 5.3917 5.3016 5.3196 21.9 22.4
5 - 5/8 5.625 5.5167 5.4266 5.4446 23 23.4
5 - 3/4 5.75 5.6417 5.5516 5.5696 24 24.5
5 - 7/8 5.875 5.7667 5.6766 5.6946 25.1 25.6
6 6 5.8917 5.8016 5.8196 26.3 26.8