Identification sheet

Japanese fittings: JIS 30 degree and Komatsu 30 degree

Two connections with the same 30 degree seat and completely different threads: one BSPP, one metric. Neither will start on the other.

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Japanese fittings: JIS 30 degree and Komatsu 30 degree

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Japanese fittings: JIS 30 degree and Komatsu 30 degree. Two connections with the same 30 degree seat and completely different threads: one BSPP, one metric. Neither will start on the other.
Size	Thread	TPI / pitch	Basic major Ø	Measured across crests	Tube OD	Working pressure
JIS 30 degree flare on a BSPP thread (JIS B 0202 thread form)
-04 JIS 30 (G 1/4)	G 1/4 (19 TPI, 55 degree)	19 TPI (1.337 mm pitch)	13.16 mm / 0.518 in	13.21 mm to 13.5 mm	Not published	Not published
-06 JIS 30 (G 3/8)	G 3/8 (19 TPI, 55 degree)	19 TPI (1.337 mm pitch)	16.66 mm / 0.656 in	16.51 mm to 16.7 mm	Not published	Not published
-08 JIS 30 (G 1/2)	G 1/2 (14 TPI, 55 degree)	14 TPI (1.814 mm pitch)	20.95 mm / 0.825 in	20.5 mm to 20.83 mm	Not published	Not published
-10 JIS 30 (G 5/8)	G 5/8 (14 TPI, 55 degree)	14 TPI (1.814 mm pitch)	22.91 mm / 0.902 in	22.35 mm to 23.1 mm	Not published	Not published
-12 JIS 30 (G 3/4)	G 3/4 (14 TPI, 55 degree)	14 TPI (1.814 mm pitch)	26.44 mm / 1.041 in	26.3 mm to 26.42 mm	Not published	Not published
-16 JIS 30 (G 1)	G 1 (11 TPI, 55 degree)	11 TPI (2.309 mm pitch)	33.25 mm / 1.309 in	33.02 mm to 33.4 mm	Not published	Not published
-20 JIS 30 (G 1 1/4)	G 1 1/4 (11 TPI, 55 degree)	11 TPI (2.309 mm pitch)	41.91 mm / 1.65 in	41.91 mm to 42.1 mm	Not published	Not published
-24 JIS 30 (G 1 1/2)	G 1 1/2 (11 TPI, 55 degree)	11 TPI (2.309 mm pitch)	47.8 mm / 1.882 in	47.6 mm to 47.75 mm	Not published	Not published
-32 JIS 30 (G 2)	G 2 (11 TPI, 55 degree)	11 TPI (2.309 mm pitch)	59.61 mm / 2.347 in	59.6 mm to 59.69 mm	Not published	Not published
Komatsu style 30 degree flare on a metric thread
M18 x 1.5 Komatsu 30	M18 x 1.5	1.5 mm pitch	18 mm / 0.709 in	Not published	Not published	Not published
M22 x 1.5 Komatsu 30	M22 x 1.5	1.5 mm pitch	22 mm / 0.866 in	Not published	Not published	Not published
M24 x 1.5 Komatsu 30	M24 x 1.5	1.5 mm pitch	24 mm / 0.945 in	Not published	16 mm	Not published
M30 x 1.5 Komatsu 30	M30 x 1.5	1.5 mm pitch	30 mm / 1.181 in	Not published	19 mm	Not published
M33 x 1.5 Komatsu 30	M33 x 1.5	1.5 mm pitch	33 mm / 1.299 in	Not published	25 mm	Not published
M36 x 1.5 Komatsu 30	M36 x 1.5	1.5 mm pitch	36 mm / 1.417 in	Not published	32 mm	Not published
M42 x 1.5 Komatsu 30	M42 x 1.5	1.5 mm pitch	42 mm / 1.654 in	Not published	38 mm	Not published

Sources: ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads, Table 1 (ISO); Hydraulic coupling identification chart E2/50101 (Gates); Fluid Ports and Connectors Identification Guide (McGill Hose & Coupling).

Reference aid for identification and ordering, not a substitute for the manufacturer specification. Pressure ratings apply only under the conditions printed beside them. Verify against the maker's catalogue before a system is charged.

Free to read

Every figure on this sheet, on its own page

Nothing on this sheet is behind the paywall as information. Each standard below has a free index carrying the same table, and each size has its own page with the measured span, the seat, what it mates with and the sources behind every figure.

JIS 30 degree flare (BSPP)9 sizes, freeJIS B 0202, ISO 228-1 Komatsu 30 degree flare (metric)7 sizes, freeISO 261, manufacturer catalogue dimensions

More sheets

Other identification charts

SAE inch fittings: JIC 37, ORB, ORFS and SAE 4542 rows Pipe threads: NPT, BSPP and BSPT32 rows Metric DIN 2353 / ISO 8434-1, light and heavy series20 rows Seat and thread identification: all ten standards10 rows Published working pressures, with the conditions they apply under61 rows

Where these figures come from

Every value on this page was checked against 3 independent published sources:

ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads, Table 1 - ISO, ISO 228-1:2000(E), fourth edition (standard, read directly, read 2026-08-27)
Hydraulic coupling identification chart E2/50101 - Gates, Gates Europe, 2004 (manufacturer, read 2026-08-27)
Fluid Ports and Connectors Identification Guide - McGill Hose & Coupling, SAE J512, J514, J1453, J1926-1, ISO 228, ISO 7, DIN 2353, JIS (distributor, read 2026-08-27)