
Barrel Nipple
A list of 16 thread sizes are defined by the standards, ranging from 1⁄16″ to 6″. The size was originally based on the inner diameter measured in inches of a steel tube for which the thread was intended. This often causes confusion, as people think the size refers to the outside diameter of the male thread.
Parallel (straight) threads, British Standard Pipe Parallel thread (BSPP)The table below shows dimensions for male threads.
PHOTO IS FOR ILLUSTRATION PURPOSE ONLY
G / R size | Thread pitch | Major diameter | Minor diameter | Gauge length | Tapping drill | |||||
---|---|---|---|---|---|---|---|---|---|---|
R 95% | G 80% | |||||||||
(in) | (in−1) | (mm) | (in) | (mm) | (in) | (mm) | (in) | (mm) | (mm) | (mm) |
1⁄16 | 28 | 0.907 | 0.3041 | 7.723 | 0.2583 | 6.561 | 5⁄32 | 4.0 | 6.6 | 6.8 |
1⁄8 | 28 | 0.907 | 0.3830 | 9.728 | 0.3372 | 8.566 | 5⁄32 | 4.0 | 8.6 | 8.8 |
1⁄4 | 19 | 1.337 | 0.5180 | 13.157 | 0.4506 | 11.445 | .2367 | 6.0 | 11.5 | 11.8 |
3⁄8 | 19 | 1.337 | 0.6560 | 16.662 | 0.5886 | 14.950 | 1⁄4 | 6.4 | 15.0 | 15.3 |
1⁄2 | 14 | 1.814 | 0.8250 | 20.955 | 0.7335 | 18.631 | .3214 | 8.2 | 18.7 | 19.1 |
5⁄8 | 14 | 1.814 | 0.9020 | 22.911 | 0.8105 | 20.587 | .3214 | 8.2 | 20.7 | 21.1 |
3⁄4 | 14 | 1.814 | 1.0410 | 26.441 | 0.9495 | 24.117 | 3⁄8 | 9.5 | 24.2 | 24.6 |
7⁄8 | 14 | 1.814 | 1.1890 | 30.201 | 1.0975 | 27.877 | 3⁄8 | 9.5 | 28.0 | 28.3 |
1 | 11 | 2.309 | 1.3090 | 33.249 | 1.1926 | 30.291 | .4091 | 10.4 | 30.4 | 30.9 |
1 1⁄8 | 11 | 2.309 | 1.4920 | 37.897 | 1.3756 | 34.939 | .4091 | 10.4 | 35.1 | 35.5 |
1 1⁄4 | 11 | 2.309 | 1.6500 | 41.910 | 1.5335 | 38.952 | 1⁄2 | 12.7 | 39.1 | 39.5 |
1 3⁄8 | 11 | 2.309 | 1.7450 | 44.323 | 1.6285 | 41.365 | 1⁄2 | 12.7 | 41.5 | 42.0 |
1 1⁄2 | 11 | 2.309 | 1.8820 | 47.803 | 1.7656 | 44.845 | 1⁄2 | 12.7 | 45.0 | 45.4 |
1 5⁄8 | 11 | 2.309 | 2.0820 | 52.883 | 1.9656 | 49.926 | 5⁄8 | 15.9 | 50.1 | 50.5 |
1 3⁄4 | 11 | 2.309 | 2.1160 | 53.746 | 1.9995 | 50.788 | 5⁄8 | 15.9 | 50.9 | 51.4 |
1 7⁄8 | 11 | 2.309 | 2.2440 | 56.998 | 2.1276 | 54.041 | 5⁄8 | 15.9 | 54.2 | 54.6 |
2 | 11 | 2.309 | 2.3470 | 59.614 | 2.2306 | 56.656 | 5⁄8 | 15.9 | 56.8 | 57.2 |
2 1⁄4 | 11 | 2.309 | 2.5870 | 65.710 | 2.4706 | 62.752 | 11⁄16 | 17.5 | 62.9 | 63.3 |
2 1⁄2 | 11 | 2.309 | 2.9600 | 75.184 | 2.8435 | 72.226 | 11⁄16 | 17.5 | 72.4 | 72.8 |
2 3⁄4 | 11 | 2.309 | 3.2100 | 81.534 | 3.0935 | 78.576 | 13⁄16 | 20.6 | 78.7 | 79.2 |
3 | 11 | 2.309 | 3.4600 | 87.884 | 3.3435 | 84.926 | 13⁄16 | 20.6 | 85.1 | 85.5 |
3 1⁄4 | 11 | 2.309 | 3.7000 | 93.980 | 3.5835 | 91.022 | 7⁄8 | 22.2 | 91.2 | 91.6 |
3 1⁄2 | 11 | 2.309 | 3.9500 | 100.330 | 3.8335 | 97.372 | 7⁄8 | 22.2 | 97.5 | 98.0 |
3 3⁄4 | 11 | 2.309 | 4.2000 | 106.680 | 4.0835 | 103.722 | 7⁄8 | 22.2 | 103.9 | 104.3 |
4 | 11 | 2.309 | 4.4500 | 113.030 | 4.3335 | 110.072 | 1 | 25.4 | 110.2 | 110.7 |
4 1⁄2 | 11 | 2.309 | 4.9500 | 125.730 | 4.8335 | 122.772 | 1 | 25.4 | 122.9 | 123.4 |
5 | 11 | 2.309 | 5.4500 | 138.430 | 5.3335 | 135.472 | 1 1⁄8 | 28.6 | 135.6 | 136.1 |
5 1⁄2 | 11 | 2.309 | 5.9500 | 151.130 | 5.8335 | 148.172 | 1 1⁄8 | 28.6 | 148.3 | 148.8 |
6 | 11 | 2.309 | 6.4500 | 163.830 | 6.3335 | 160.872 | 1 1⁄8 | 28.6 | 161.0 | 161.5 |
7 | 10 | 2.540 | 7.4500 | 189.230 | 7.3220 | 185.979 | 1 3⁄8 | 34.9 | 186.1 | 186.6 |
8 | 10 | 2.540 | 8.4500 | 214.630 | 8.3220 | 211.379 | 1 1⁄2 | 38.1 | 211.5 | 212.0 |
9 | 10 | 2.540 | 9.4500 | 240.030 | 9.3220 | 236.779 | 1 1⁄2 | 38.1 | 236.9 | 237.4 |
10 | 10 | 2.540 | 10.4500 | 265.430 | 10.3220 | 262.179 | 1 5⁄8 | 41.3 | 262.3 | 262.8 |
11 | 8 | 3.175 | 11.4500 | 290.830 | 11.2900 | 286.766 | 1 5⁄8 | 41.3 | 287.0 | 287.6 |
12 | 8 | 3.175 | 12.4500 | 316.230 | 12.2900 | 312.166 | 1 5⁄8 | 41.3 | 312.4 | 313.0 |
13 | 8 | 3.175 | 13.6800 | 347.472 | 13.5200 | 343.408 | 1 5⁄8 | 41.3 | 343.6 | 344.2 |
14 | 8 | 3.175 | 14.6800 | 372.872 | 14.5200 | 368.808 | 1 3⁄4 | 44.5 | 369.0 | 369.6 |
15 | 8 | 3.175 | 15.6800 | 398.272 | 15.5200 | 394.208 | 1 3⁄4 | 44.5 | 394.4 | 395.0 |
16 | 8 | 3.175 | 16.6800 | 423.672 | 16.5200 | 419.608 | 1 7⁄8 | 47.6 | 419.8 | 420.4 |
17 | 8 | 3.175 | 17.6800 | 449.072 | 17.5200 | 445.008 | 2 | 50.8 | 445.2 | 445.8 |
18 | 8 | 3.175 | 18.6800 | 474.472 | 18.5200 | 470.408 | 2 | 50.8 | 470.6 | 471.2 |