4-4.Taper female thread for pipes
[JIS B 0203]
unit=mm
*Nominal screw Thread Reference diameter Reference diameter position Effective thread length（minimum） Dimensions of carbon steel pipes for piping（reference）
Number of threads　n　　　　　　（25.Per 4mm) Pitch P(reference) Mountain height h Roundness r Or r’ Female thread Female thread Female thread
Valley diameter D Effective diameter D2 Inner diameter D1 Tube end If there is an incomplete thread When there is no incomplete thread
Axial tolerance ｃ Tapered female thread Parallel female thread Tapered female thread，Parallel female thread Outer diameter thickness
From the position of the reference diameter toward the small diameter side　l From the end of a pipe or fitting　l'　 ○t　
R1/16 28 0.9071 0.581 0.12 7.723 7.142 6.561 ±1.13 6.2 7.4 4.4 ― ―
R1/8 28 0.9071 0.581 0.12 9.728 9.147 8.566 ±1.13 6.2 7.4 4.4 10.5 2.0
R1/4 19 1.3368 0.856 0.18 13.157 12.301 11.445 ±1.67 9.4 11.0 6.7 13.8 2.3
R3/8 19 1.3368 0.856 0.18 16.662 15.806 14.950 ±1.67 9.7 11.4 7.0 17.3 2.3
R1/2 14 1.8143 1.162 0.25 20.955 19.793 18.631 ±2.27 12.7 15.0 9.1 21.7 2.8
R3/4 14 1.8143 1.162 0.25 26.441 25.279 24.117 ±2.27 14.1 16.3 10.2 27.2 2.8
R1 11 2.3091 1.479 0.32 33.249 31.770 30.291 ±2.89 16.2 19.1 11.6 34 3.2
R1 1/4 11 2.3091 1.479 0.32 41.910 40.431 38.952 ±2.89 18.5 21.4 13.4 42.7 3.5
R1 1/2 11 2.3091 1.479 0.32 47.803 46.324 44.845 ±2.89 18.5 21.4 13.4 48.6 3.5
R2 11 2.3091 1.479 0.32 59.614 58.135 56.656 ±2.89 22.8 25.7 16.9 60.5 3.8
R2 1/2 11 2.3091 1.479 0.32 75.184 73.705 72.226 ±3.46 26.7 30.1 18.6 76.3 4.2
R3 11 2.3091 1.479 0.32 87.884 86.405 84.926 ±3.46 29.8 33.3 21.1 89.1 4.2
R4 11 2.3091 1.479 0.32 113.030 111.551 110.072 ±3.46 35.8 39.3 25.9 114.3 4.5
R5 11 2.3091 1.479 0.32 138.430 136.951 135.472 ±3.46 40.1 43.5 29.3 139.8 4.5
R6 11 2.3091 1.479 0.32 163.830 162.351 160.872 ±3.46 40.1 43.5 29.3 165.2 5.0
* For tapered female threads and parallel female threads, the symbol of R is R C or R P .
○Tapered threads are the length from the reference diameter position toward the smaller diameter side, and parallel female threads are the length from the end of the pipe or fitting.
References: "JIS Handbook 2002 (4-1) Screw I Terms / Expression / Drafting / Basic / Limit Gauge / Common to Parts" (Japanese Standards Association) Tapered Thread for Pipes Page 90 Appendix 1 Standard chevron, standard dimensions and dimensions Quoted from tolerance.