International Measuring and Identification Guide - JIS (Japanese Industrial Standard) - Tapered Pipe - JIS B 0203

ThreadThread O.D.Female Thread I.D.
SizeMMFrac.MMFrac.
1/8 - 289.53/88.711/32
1/4 - 1913.717/3212.41/2
3/8 - 1917.211/1616.05/8
1/2 - 1421.527/3219.825/32
3/4 - 1426.91 1/1625.41
1 - 1134.01 11/3231.81 1/4
1 1/4 - 1142.61 11/1640.41 19/32
1 1/2 - 1148.51 29/3246.21 27/32
2 - 1160.42 3/858.22 5/16
The Japanese tapered pipe thread connector is similar to the BSPT in design, appearance and dimensions.
The JIS tapered pipe thread and BSPT tapered thread are interchangeable.
The seal on JIS tapered pipe thread is made on the threads.
The threads retain the connection.