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Tapered Pipe Threads (Excerpt from JIS B 0203:1999)

Standard profile

Standard profiles applied to tapered male threads and tapered female threads

Standard profile_1

Standard profile applied to parallel female thread

Standard profile_2

Tapered male thread fitting with tapered female thread and parallel female thread

Standard profile_3

Standard dimensions

Nominal thread size (1) Screw thread Standard diameter Standard diameter position Tolerance of D, D2, and D1 in parallel female threads Length of effective thread section (minimum) Dimensions of carbon steel pipe (reference)
Number of screw threads (number per 25.4 mm) Pitch p (reference) Thread height h Roundness r or r' Male thread Male thread Female thread Male thread Female thread
Length toward the large diameter side from the standard diameter position f With an incomplete thread section Without an incomplete thread section
Outer diameter d Effective diameter d2 Valley diameter d1 From pipe end Pipe end
Tapered female thread Parallel female thread Tapered female thread and parallel female thread
Female thread Standard length a Tolerance in the shaft line direction b Tolerance in the shaft line direction c
Valley diameter D Effective diameter D2 Inner diameter D1 Length toward the small diameter side from standard diameter position ℓ Length from pipe or pipe fitting end ℓ'(reference) t(2) Outer diameter Thickness
R1/16 28 0.9071 0.581 0.12 7.723 7.142 6.561 3.97 ±0.91  ±1.13  ±0.071  2.5 6.2 7.4 4.4
R1/8 28 0.9071 0.581 0.12 9.728 9.147 8.566 3.97 ±0.91  ±1.13  ±0.071  2.5 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 6.01 ±1.34  ±1.67  ±0.104  3.7 9.4 11 6.7 13.8 2.3
                                   
R3/8 19 1.3368 0.856 0.18 16.662 15.806 14.95 6.35 ±1.34  ±1.67 ±0.104  3.7 9.7 11.4 7 17.3 2.3
R1/2  14 1.8143 1.162 0.25 20.955 19.793 18.631 8.16 ±1.81  ±2.27  ±0.142  5 12.7 15 9.1 21.7 2.8
R3/4  14 1.8143 1.162 0.25 26.441 25.279 24.117 9.53 ±1.81  ±2.27  ±0.142  5 14.1 16.3 10.2 27.2 2.8
                                   
R1  11 2.3091 1.479 0.32 33.249 31.77 30.291 10.39 ±2.31  ±2.89  ±0.181  6.4 16.2 19.1 11.6 34 3.2
R1 1/4  11 2.3091 1.479 0.32 41.91 40.431 38.952 12.7 ±2.31  ±2.89  ±0.181  6.4 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 12.7 ±2.31  ±2.89  ±0.181  6.4 18.5 21.4 13.4 48.6 3.5
                                   
R2  11 2.3091 1.479 0.32 59.614 58.135 56.656 15.88 ±2.31  ±2.89  ±0.181  7.5 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 17.46 ±3.46  ±3.46  ±0.216  9.2 26.7 30.1 18.6 76.3 4.2
R3  11 2.3091 1.479 0.32 87.884 86.405 84.926 20.64 ±3.46  ±3.46  ±0.216  9.2 29.8 33.3 21.1 89.1 4.2

Notes

  • (1) This nominal thread size is for tapered male threads. For tapered female threads and parallel female threads, replace the R symbol with Rc or Rp (refer to *).
  • (2) For tapered male threads, this is the length toward the small diameter side from the standard diameter position. For tapered female threads, this is the length from the pipe or pipe fitting end.

Remarks

  • 1. The screw thread is at a right angle to the central shaft line, and the pitch is measured along the central shaft line.
  • 2. The effective length of the thread section is the length of the completely-cut thread section. The surface of pipe or pipe fitting may remain on the last several threads.
    Besides, even if the end of the pipe or pipe fitting is chamfered, this section is included in the effective thread section length.
  • 3. If it is difficult to use this table for values a, f, and t, refer to separately established component standards.
  • *Tapered pipe threads include male tapered pipe threads, female tapered pipe threads, and female parallel pipe threads.
    This parallel pipe thread is to be used with male tapered pipe threads, and the dimensional tolerance is different from that of the parallel pipe thread regulated in JIS B 0202.

Recommended Products

Steel Pipes, Copper Pipes, Stainless Steel Pipes, Resin Pipes

Fittings

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