4-3.Taper male 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’ Male screw Male screw Male screw
Outer diameter　　　d Effective diameter d2 Valley diameter d1 From the end of the pipe From the position of the reference diameter toward the large diameter side　f Outer diameter thickness
Reference length a Axial tolerance b
R1/16 28 0.9071 0.581 0.12 7.723 7.142 6.561 3.97 ±0.91 2.5 ― ―
R1/8 28 0.9071 0.581 0.12 9.728 9.147 8.566 3.97 ±0.91 2.5 10.5 2.0
R1/4 19 1.3368 0.856 0.18 13.157 12.301 11.445 6.01 ±1.34 3.7 13.8 2.3
R3/8 19 1.3368 0.856 0.18 16.662 15.806 14.950 6.35 ±1.34 3.7 17.3 2.3
R1/2 14 1.8143 1.162 0.25 20.955 19.793 18.631 8.16 ±1.81 5.0 21.7 2.8
R3/4 14 1.8143 1.162 0.25 26.441 25.279 24.117 9.53 ±1.81 5.0 27.2 2.8
R1 11 2.3091 1.479 0.32 33.249 31.770 30.291 10.39 ±2.31 6.4 34 3.2
R1 1/4 11 2.3091 1.479 0.32 41.910 40.431 38.952 12.70 ±2.31 6.4 42.7 3.5
R1 1/2 11 2.3091 1.479 0.32 47.803 46.324 44.845 12.70 ±2.31 6.4 48.6 3.5
R2 11 2.3091 1.479 0.32 59.614 58.135 56.656 15.88 ±2.31 7.5 60.5 3.8
R2 1/2 11 2.3091 1.479 0.32 75.184 73.705 72.226 17.46 ±3.46 9.2 76.3 4.2
R3 11 2.3091 1.479 0.32 87.884 86.405 84.926 20.64 ±3.46 9.2 89.1 4.2
R4 11 2.3091 1.479 0.32 113.030 111.551 110.072 25.40 ±3.46 10.4 114.3 4.5
R5 11 2.3091 1.479 0.32 138.430 136.951 135.472 28.58 ±3.46 11.5 139.8 4.5
R6 11 2.3091 1.479 0.32 163.830 162.351 160.872 28.58 ±3.46 11.5 165.2 5.0
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.