Thread charts
| Whitworth pipe thread (cylindrical). DIN 259 (ISO 228) | |||||||
| Thread | G1/8″ | G1/4″ | G3/8″ | G1/2″ | G5/8″ | G3/4″ | G7/8″ |
| Thread diameter mm | 9.728 | 13.157 | 16.662 | 20.955 | 22.911 | 26.441 | 30.201 |
| Core diameter mm | 8.566 | 11.445 | 14.950 | 18.631 | 20.587 | 24.117 | 27.877 |
| Number of turns in 1” (= 25.4 cm) | 28 | 19 | 19 | 14 | 14 | 14 | 14 |
| Thread | G2 1/4″ | G2 3/8″ | G2 1/2″ | G2 3/4″ | G3″ | G3 1/4″ | G3 1/2″ |
| Thread diameter mm | 65.710 | 69.390 | 75.184 | 81.534 | 87.884 | 93.980 | 100.330 |
| Core diameter mm | 62.752 | 66.440 | 72.226 | 78.577 | 84.926 | 91.022 | 97.372 |
| Number of threads in 1” (= 25.4 cm) | 11 | 11 | 11 | 11 | 11 | 11 | 11 |
| Thread | G1″ | G1 1/8″ | G1 1/4″ | G1 3/8″ | G1 1/2″ | G1 3/4″ | G 2″ |
| Thread diameter mm | 33.249 | 37.897 | 41.910 | 44.323 | 47.803 | 53.746 | 59.614 |
| Core diameter mm | 30.291 | 34.939 | 38.952 | 41.365 | 44.845 | 50.788 | 56.656 |
| Number of turns in 1” (= 25.4 cm) | 11 | 11 | 11 | 11 | 11 | 11 | 11 |
| Thread | G3 3/4″ | G4″ | G4 1/2″ | G5″ | G5 1/2″ | G6″ | |
| Thread diameter mm | 106.680 | 113.030 | 125.730 | 138.430 | 151.130 | 163.830 | |
| Core diameter mm | 103.722 | 110.072 | 122.772 | 135.472 | 148.172 | 160.872 | |
| Number of threads in 1” (= 25.4 cm) | 11 | 11 | 11 | 11 | 11 | 11 | |
| Whitworth pipe thread (conical). DIN 2999 (ISO 7/1) Rp-R BS 21 (BSP-BSPT) | |||||||
| Thread | R1/8″ | R1/4″ | R3/8″ | R1/2″ | R5/8″ | R3/4″ | R7/8″ |
| Thread diameter mm | 9.728 | 13.157 | 16.662 | 20.955 | 22.911 | 26.441 | 30.201 |
| Core diameter mm | 8.566 | 11.445 | 14.950 | 18.631 | 20.587 | 24.117 | 27.877 |
| Number of threads in 1” (= 25.4 cm) | 28 | 19 | 19 | 14 | 14 | 14 | 14 |
| Thread | R2 1/4″ | R2 3/8″ | R2 1/2″ | R2 3/4″ | R3″ | R3 1/4″ | R3 1/2″ |
| Thread diameter mm | 65.710 | 69.390 | 75.184 | 81.534 | 87.884 | 93.980 | 100.330 |
| Core diameter mm | 62.752 | 66.440 | 72.226 | 78.577 | 84.926 | 91.022 | 97.372 |
| Number of threads in 1” (= 25.4 cm) | 11 | 11 | 11 | 11 | 11 | 11 | 11 |
| Thread | R1″ | R1 1/8″ | R1 1/4″ | R1 3/8″ | R1 1/2″ | R1 3/4″ | R2″ |
| Thread diameter mm | 33.249 | 37.897 | 41.910 | 44.323 | 47.803 | 53.746 | 59.614 |
| Core diameter mm | 30.291 | 34.939 | 38.952 | 41.365 | 44.845 | 50.788 | 56.656 |
| Number of threads in 1” (= 25.4 cm) | 11 | 11 | 11 | 11 | 11 | 11 | 11 |
| Thread | R3 3/4″ | R4″ | R4 1/2″ | R5″ | R5 1/2″ | R6″ | |
| Thread diameter mm | 106.680 | 113.030 | 125.730 | 138.430 | 151.130 | 163.830 | |
| Core diameter mm | 103.722 | 110.072 | 122.772 | 135.472 | 148.172 | 160.872 | |
| Number of threads in 1” (= 25.4 cm) | 11 | 11 | 11 | 11 | 11 | 11 | |
| American pipe thread NPT (conical). ASA B 2.1 | |||||||
| Thread | 1/8″NPT | 1/4″NPT | 3/8″NPT | 1/2″NPT | 3/4″NPT | 1″NPT | 11/4″NPT |
| Thread diameter mm | 10.287 | 13.716 | 17.145 | 21.336 | 26.670 | 33.401 | 42.164 |
| Number of threads in 1” (= 25.4 cm) | 27 | 18 | 18 | 14 | 14 | 11 1/2 | 11 1/2 |
| Thread | 11/2″NPT | 2″NPT | |||||
| Thread diameter mm | 48.260 | 60.325 | |||||
| Number of threads in 1” (= 25.4 cm) | 11 1/2 | 11 1/2 | |||||
