JIS Threads
JIS is JAPANESE INDUSTRIAL STANDARDS
There are four popular coupling styles in Japan
1. JIS Tapered Pipe Thread
The Japanese tapered pipe thread connector is identical to and interchangeable with the BSPT (tapered) connector. The Japanese male thread does not have a 30° Flare, and will not mate with the BSPP female swivel with conical seat.
The seal on the Japanese tapered pipe thread connector is made on the threads. Use of a thread sealant is recommended.
Thread form per JIS B 0203 (identical to BSPT)
2. JIS 30° Flare (Female Internal Cone Seat)
This connection uses a 60° concave (inverted) seat and British Standard Pipe Parallel threads. They are not interchangeable with BSPP conical seat couplings, because the cone seats are opposite.
Thread form per JIS B 0202 (identical to BSPP)
3. Komatsu 30° flare (Female Internal Cone Seat)
Threads commonly used on Komatsu equipment (30° cone) have metric thread form.
| MALE THREAD OD & PITCH | DASH SIZE | FEMALE THREAD ID |
|---|---|---|
| mm | mm | |
| M14 x 1,5 | -1415 | 12,5 |
| M18 x 1,5 | -1815 | 16,5 |
| M22 x 1,5 | -2215 | 20,5 |
| M24 x 1,5 | -2415 | 22,5 |
| M30 x 1,5 | -3015 | 28,5 |
| M33 x 1,5 | -3315 | 31,5 |
| M36 x 1,5 | -3615 | 34,5 |
| M33 x 1,5 | -3315 | 31,5 |
4. Komatsu Style Flange Fitting JIS B 8363
The Komatsu style Flange fitting is nearly identical to, and fully interchangeable with, the SAE Code 61 flange fitting*. The O Ring dimensions are different between all sizes. When replacing a Komatsu style flange with an SAE style flange, an SAE style O Ring must always be used. *5/8” is not in the SAE Standards.
BSPT & BSPP Threads Dimensions
| BSPT & BSPP SIZE & PITCH | DASH SIZE | BSPT MALE THREAD OD | BSPP MALE THREAD OD | BSPT FEMALE THREAD ID | BSPP FEMALE THREAD ID | ||||
|---|---|---|---|---|---|---|---|---|---|
| inch-TPI | mm | inch | mm | inch | mm | inch | mm | inch | |
| 1/8 – 28 | -02 | 9,5 | 0.37 | 9,6 | 0.38 | 8,4 | 0.33 | 8,6 | 0.34 |
| 1/4 – 19 | -04 | 12,8 | 0.50 | 13,0 | 0.51 | 11,2 | 0.44 | 11,9 | 0.47 |
| 3/8 – 19 | -06 | 16,3 | 0.64 | 16,5 | 0.65 | 14,7 | 0.59 | 15,2 | 0.60 |
| 1/2 – 14 | -08 | 20,4 | 0.80 | 20,8 | 0.82 | 18,3 | 0.72 | 19,1 | 0.75 |
| 5/8 – 14 | -10 | 22,5 | 0.89 | 22,8 | 0.90 | 20,6 | 0.81 | 20,8 | 0.82 |
| 3/4 – 14 | -12 | 25,9 | 1.02 | 26,3 | 1.04 | 23,9 | 0.94 | 24,6 | 0.97 |
| 1 – 11 | -16 | 32,6 | 1.28 | 33,1 | 1.30 | 29,7 | 1.17 | 30,7 | 1.21 |
| 1.1/4 – 11 | -20 | 41,1 | 1.62 | 41,8 | 1.64 | 38,6 | 1.52 | 39,4 | 1.55 |
| 1.1/2 – 11 | -24 | 47,0 | 1.85 | 47,7 | 1.88 | 44,5 | 1.75 | 45,5 | 1.79 |
| 2 -11 | -32 | 58,6 | 2.31 | 59,5 | 2.34 | 56,4 | 2.22 | 57,4 | 2.26 |
| 2.1/2 – 11 | -40 | 74,1 | 2.92 | 75,1 | 2.95 | 71,9 | 2.83 | 72,6 | 2.86 |
| 3 – 11 | -48 | 86,6 | 3.41 | 87,9 | 3.46 | 84,6 | 3.33 | 85,4 | 3.36 |
Thread size refers to the nominal bore of the pipe.
Subtract approx.1/4″ (6 mm) from thread diameter measurement for nominal pipe size.
Pitch is Threads Per Inch (TPI). “Gas”, “R” & “G” also refer to BSP. “Male Iron (Pipe)” may be BSP or NPT.