Coupling Identification - Japanese
There are five coupling systems generally used for hydraulic connections today. They are identified geographically or by country as:
Japanese Thread Types
There are two popular coupling styles in Japan:
- All Komatsu equipment uses couplings with a 30° seat and metric fine threads. All flanges are Code 61 or Code 62 (except -10)*.
- Most other Japanese equipment uses couplings with a 30° seat and British Standard Pipe Parallel threads, usually called JIS (Japanese Industrial Standard) couplings. They are not interchangeable with British couplings, since the flare is not inverted. All flanges are Code 61 or Code 62 (except -10)*.
*(-10 is a non-SAE size flange)
Japanese 30° Flare Parallel Threads
These Japanese 30° flare male connector will mate with a Japanese 30° flare female only.
The male and female have straight threads and a 30° seat. The seal is made on a 30° seat.
The threads on the Japanese 30° flare connector conform to JIS B 0202, which are the same as the BSPP threads. Both the British and Japanese connectors have a 30° seat, but they are not interchangeable, because the British seat is inverted.
Japanese 30° Flare Parallel Threads
| Dash Size | Nominal Size in. | Thread Size | Male Thread O.D. in. | Female Thread I.D. in. |
| -2 | 1/8 | 1/8-28 | 3/8 | 11/32 |
| -4 | 1/4 | 1/4-19 | 17/32 | 7/16 |
| -6 | 3/8 | 3/8-19 | 21/32 | 19/32 |
| -8 | 1/2 | 1/2-14 | 13/16 | 3/4 |
| -10 | 5/8 | 5/8-14 | 29/32 | 13/16 |
| -12 | 3/4 | 3/4-14 | 1 1/32 | 15/16 |
| -16 | 1 | 1-11 | 1 5/16 | 1 3/16 |
| -20 | 1 1/4 | 1 1/4-11 | 1 21/32 | 1 17/32 |
| -24 | 1 1/2 | 1 1/2-11 | 1 7/8 | 1 25/32 |
| -32 | 2 | 2-11 | 1 11/32 | 2 7/32 |
Japanese Tapered Pipe Thread
The Japanese tapered pipe thread connector is identical to and fully interchangeable with the BSPT (tapered) connector. The Japanese connector does not have a 30° Flare, and will not mate with the BSPP female.
The threads conform to JIS B 0203, which are the same as BSPT threads.
The seal on the Japanese tapered pipe thread connector is made on the threads.
Japanese Tapered Pipe Thread
| Dash Size | Nominal Size in. | Thread Size | Male Parallel Thread O.D. in. | Female Parallel Thread I.D.in. |
| -2 | 1/8 | 1/8-28 | 3/8 | 11/32 |
| -4 | 1/4 | 1/4-19 | 17/32 | 7/16 |
| -6 | 3/8 | 3/8-19 | 21/32 | 19/32 |
| -8 | 1/2 | 1/2-14 | 13/16 | 3/4 |
| -12 | 3/4 | 3/4-14 | 1 1/32 | 15/16 |
| -16 | 1 | 1-11 | 1 5/16 | 1 3/16 |
| -20 | 1 1/4 | 1 1/4-11 | 1 21/32 | 1 17/32 |
| -24 | 1 1/2 | 1 1/2-11 | 1 7/8 | 1 25/32 |
| -32 | 2 | 2-11 | 2 11/32 | 2 7/32 |
Komatsu Style 30° Flare Parallel Threads
The Komatsu Style 30° Flare parallel thread connector is identical to the Japanese 30° Flare parallel thread connector except for the threads. The Komatsu style connector uses Metric fine threads which conform to JIS B 0207.
The Komatsu style connector seals on the 30° Flare.
Komatsu Style 30° Flare Parallel Threads
| Dash Size | Nominal Size | Metric Thread Size | Male Parallel Thread O.D. mm | Female Parallel Thread I.D. mm | |
| in. | mm | ||||
| -6 | 3/8 | 9.5 | M18x1.5 | 18 | 16.5 |
| -8 | 1/2 | 13 | M22x1.5 | 22 | 20.5 |
| -10 | 5/8 | 16 | M24x1.5 | 24 | 22.5 |
| -12 | 3/4 | 19 | M30x1.5 | 30 | 28.5 |
| -16 | 1 | 25 | M33x1.5 | 33 | 31.5 |
| -20 | 1 1/4 | 32 | M36x1.5 | 36 | 34.5 |
| -24 | 1 1/2 | 38 | M42x1.5 | 42 | 40.5 |
Komatsu Style Flange Fitting
The Komatsu Style Flange fitting is nearly identical to and fully interchangeable with the SAE Code 61 flange fitting. In all sizes the O-ring dimensions are different. When replacing a Komatsu style flange with an SAE style flange, an SAE style O-ring must always be used.
Komatsu Style Flange Fitting
| Dash Size | Nominal Size | Flange O.D. in. | A in. | B in. | |
| in. | mm | ||||
| -8 | 1/2 | 12.7 | 1.188 | .728 | .984 |
| -10* | 5/8 | 15.9 | 1.345 | .728 | 1.102 |
| -12 | 3/4 | 19.1 | 1.500 | .846 | 1.220 |
| -16 | 1 | 25.4 | 1.750 | 1.122 | 1.496 |
| -20 | 1 1/4 | 31.8 | 2.000 | 1.358 | 1.732 |
| -24 | 1 1/2 | 38.1 | 2.375 | 1.750 | 2.125 |
| -32 | 2 | 50.8 | 2.812 | 2.225 | 2.559 |
*(-10 is a non-SAE size flange)