BSP THREAD CHART

BSP thread chart showing pipe thread dimensions of ISO 228 BSPP (parallel straight threads) and IS0 7 BSPT (taper threads).BSP thread uses Whitworth thread form with flank angle of 55 , All dimension are in millimetres. The letter symbols for pipe threads are as follows:

ISO 7 Standard (BSPT Thread):

- the letter R followed by the letter p for parallel internal threads;

- the letter R followed by the letter c for taper(conical) internal threads;

 - the letter R for external threads;

ISO 228 Standard (BSPP Thread):

- the letter G for internal and external threads; (See ISO 228 BSPP (parallel straight threads) for more details)




Designation of Thread Number of threads in 25.4 mm Pitch (P) Height of thread Diameters
major (d=D) pitch (d2=D2) minor (d1=D1)
1/16 28 0.907 0.581 7.723 7.142 6.561
1/8 28 0.907 0.581 9.728 9.147 8.566
1/4 19 1.337 0.856 13.157 12.301 11.445
3/8 19 1.337 0.856 16.662 15.806 14.950
1/2 14 1.814 1.162 20.955 19.793 18.631
5/8 14 1.814 1.162 22.911 21.749 20.587
3/4 14 1.814 1.162 26.441 25.279 24.117
7/8 14 1.814 1.162 30.201 29.039 27.877
1 11 2.309 1.479 33.249 31.770 30.291
1 1/8 11 2.309 1.479 37.897 36.418 34.939
1 1/4 11 2.309 1.479 41.910 40.431 38.952
1 1/2 11 2.309 1.479 47.803 46.324 44.845
1 3/4 11 2.309 1.479 53.746 52.267 50.788
2 11 2.309 1.479 59.614 58.135 56.656
2 1/4 11 2.309 1.479 65.710 64.231 62.752
2 1/2 11 2.309 1.479 75.184 73.705 72.226
2 3/4 11 2.309 1.479 81.534 80.055 78.576
3 11 2.309 1.479 87.884 86.405 84.926
3 1/2 11 2.309 1.479 100.330 98.851 97.372
4 11 2.309 1.479 113.030 111.551 110.072
4 1/2 11 2.309 1.479 125.730 124.251 122.772
5 11 2.309 1.479 138.430 136.951 135.472
5 1/2 11 2.309 1.479 151.130 149.651 148.172
6 11 2.309 1.479 163.830 162.351 160.872




Reference:
  • ISO 228-1 :2000 Pipe threads where pressure-tight joints are not made on the threads - Part 1: Dimensions, tolerances and designation
  • ISO 7-1 :2000 Pipe Threads Where Pressure-Tight Joints are Made on the Threads - Dimensions, Tolerances and Designation