AN and JIC 37° flare fittings: dash sizes -3 to -20, thread, tube OD, hose ID, flare diameter — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/an-jic-37-degree-flare-fittings/ (sheet CC BY 4.0) Basis: AN thread (Wikipedia), Chase Bays and Hardin Marine AN charts, Ham-Let SAE 37° flare catalogue (SAE J533 flare diameter, hexes); numbers only Catalog version: 2026-10-20 Sizes: see table below - AN (and JIC) fittings seal on a 37° flare: the dash number is the tube OD in sixteenths of an inch (-6 = 6/16 = 3/8 in), not a thread. -6 is 9/16-18 UNF, -8 is 3/4-16, -10 is 7/8-14, and so on; the same threads as SAE O-ring ports. 37° AN/JIC and 45° SAE flares do not interchange. - Thread major diameters are the nominal diameter of the designation converted at 25.4 mm/in (a thread has a tolerance band). Hose ID is approximate: hose makers differ. - Flare diameter is the SAE J533 single-flare diameter range for the tube OD as printed by Ham-Let (UCT) in its 37° flare catalogue (inch values 0.26–0.28, 0.34–0.36, 0.46–0.49, 0.63–0.66, 1.17–1.20 converted to mm); wrench sizes are that maker's nut and connector hexes, and other makers differ. Charts for the other dashes did not print them. - Left out, no file: hex thickness, thread length and nose length are not printed in the charts we could read (Ham-Let prints thread, hex flats and overall length of its connectors, not the hex position), so no flare envelope is published. AN size thread (UNF/UN) tube OD hose ID flare angle SAE J533 flare dia A (mm) wrench hex (in, Ham-Let) -3 3/8-24 (major 9.52 mm) 3/16 (4.76 mm) 1/8 (approx.) 37° 6.61–7.11 - -4 7/16-20 (major 11.11 mm) 1/4 (6.35 mm) 3/16 (approx.) 37° 8.64–9.14 9/16 (nut and connector) -5 1/2-20 (major 12.70 mm) 5/16 (7.94 mm) 1/4 (approx.) 37° - - -6 9/16-18 (major 14.29 mm) 3/8 (9.52 mm) 5/16 (approx.) 37° 11.69–12.44 - -8 3/4-16 (major 19.05 mm) 1/2 (12.70 mm) 7/16 (approx.) 37° 16.01–16.76 7/8 (nut and connector) -10 7/8-14 (major 22.22 mm) 5/8 (15.88 mm) 1/2 (approx.) 37° - - -12 1-1/16-12 (major 26.99 mm) 3/4 (19.05 mm) 5/8 (approx.) 37° - - -16 1-5/16-12 (major 33.34 mm) 1 (25.40 mm) 7/8 (approx.) 37° 29.72–30.48 1-1/2 nut / 1-3/8 connector -20 1-5/8-12 (major 41.27 mm) 1-1/4 (31.75 mm) 1-1/8 (approx.) 37° - - Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Wikipedia: AN thread (sizes, 37° flare) — web — Publisher's page; dimensions are facts — https://en.wikipedia.org/wiki/AN_thread - Chase Bays: AN plumbing info and thread chart — web — Publisher's page; dimensions are facts — https://www.chasebays.com/pages/an-plumbing-info-and-thread-chart - Hardin Marine: AN fitting size guide — web — Publisher's page; dimensions are facts — https://www.hardin-marine.com/t-an-fittings-guide.aspx - Ham-Let (UCT): SAE 37° flare 3-piece tube assembly catalogue, Jan 2025 (J533 flare dia, nut and connector hexes) — web — Publisher's page; dimensions are facts — https://s29.q4cdn.com/619069826/files/doc_downloads/2025/Jan/SAE37-FLARE-2025.pdf No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned. API: https://xemstudio.com/api/geometry?object=an-jic-37-degree-flare-fittings