JIS Threads

Japanese Industrial Standards (JIS) Threads

JIS Threads

JIS Japanese Industrial Standards There are four popular couplings 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)

JIS Tapered Pipe Thread
Refer to BSPT section for dimensions of threads.

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)

JIS Komatsu Male 30degress Flare Type
Refer to BSPT section for dimensions of threads.

3. Komatsu 30° flare (Female Internal Cone Seat)

Threads commonly used on Komatsu equipment (30° cone) have metric thread form.
JIS Sealing Cone
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