The Japanese JIS 30° flare is similar to the American SAE 37° flare connection in application as well as sealing principles. However, the flare angle and dimensions are different. The threads are similar to BSPP.
Inch Size, Size mm (Dash), Nominal Thread Tapered Size, Male Thread O.D. Female Thread I.D.
1 ⁄ 4 6 (04) 1 ⁄ 4 -19 33 ⁄ 64 13,2 15 ⁄ 32 11,9
3 ⁄ 8 9 (06) 3 ⁄ 8 -19 21 ⁄ 32 16,7 19 ⁄ 32 15,3
1 ⁄ 2 12 (08) 1 ⁄ 2 -14 13 ⁄ 16 21,0 3 ⁄ 4 19,2
3 ⁄ 4 19 (12) 3 ⁄ 4 -14 1 1 ⁄ 32 26,4 31 ⁄ 32 24,6
1 25 (16) 1-11 1 5 ⁄ 16 33,3 1 7 ⁄ 32 30,9
1 1 ⁄ 4 32 (20) 1 1 ⁄ 4 -11 1 21 ⁄ 32 41,9 1 9 ⁄ 16 39,6
1 1 ⁄ 2 38 (24) 1 1 ⁄ 2 -11 1 7 ⁄ 8 47,8 1 25 ⁄ 32 45,5
2 50 (32) 2-11 2 11 ⁄ 32 59,7 2 1 ⁄ 4 57,4
