# SAE 45° flare fittings: tube OD, thread (5/16-24 to 1-1/4-12), nut hex and length, 1/8 to 7/8 in

> What thread and nut size does an SAE 45 degree flare fitting have for each tube OD?

- Category: Tri-clamp & pipe › Pipe, tube & threads
- Kind: Standard part
- Basis: Parker Hannifin catalogue 3501E (41FL, 41FS) and SC Fastening nut pages, thread list checked on McMaster-Carr; SAE J512 / J513 not read; McMaster-Carr linked for CAD
- Page: https://xemstudio.com/objects/sae-45-degree-flare-nuts-and-threads/ · JSON: https://xemstudio.com/api/geometry?object=sae-45-degree-flare-nuts-and-threads · Plain text: https://xemstudio.com/objects/sae-45-degree-flare-nuts-and-threads/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no tolerance added.

## Notes

- SAE 45° flare (the tube end is flared to 45°, the nut pulls it against a male cone). The size name is the TUBE OD; the dash number is the tube OD in sixteenths of an inch (-4 = 1/4 in tube). Threads are straight UNF: 1/8 in tube 5/16-24, 3/16 in 3/8-24, 1/4 in 7/16-20, 5/16 in 1/2-20, 3/8 in 5/8-18, 1/2 in 3/4-16, 5/8 in 7/8-14, 3/4 in 1-1/16-14, 7/8 in 1-1/4-12. These match Parker's catalogue for every size and the thread list on McMaster-Carr's 45° flared fittings page. The governing standards are SAE J512 and J513; their text is paywalled and was not read.
- Do not mix with 37° (AN / JIC) or with compression nuts: 1/4 in flare is 7/16-20 (this page), 1/4 in compression is 7/16-24, and the 37° AN -4 is also 7/16-20 with a different seat. See 'an-jic-37-degree-flare-fittings' for 37°. A 7/16-20 nut cross-threads on a 7/16-24 fitting, and 45° and 37° seats leak against each other.
- Numbers: Parker catalogue 3501E (long nut 41FL and short nut 41FS / 41FX, pages H4-H10, read through a SlideShare copy): hex c, length l and a dimension 'd' that Parker's page labels without a definition (it is the tube OD plus about 0.007 in); the 41FX 'shorter' nut (3/8 l 0.91, 1/2 l 1.00, 5/8 l 1.06, 3/4 l 1.17) is not tabulated. SC Fastening's catalogue pages give an independent set for a short rod nut (A = length, hex): its A and hex equal Parker's short nut for 1/8, 3/16, 1/4, 5/16 in (hex 0.37 vs 3/8 and so on is rounding); its long forged nut differs from Parker's long nut (1/4 in hex 0.62 vs 9/16, 3/8 in A 1.06 vs l 1.31), so both are shown rather than merged. Dash sizes follow Parker's part numbers (41FS-2 to 41FS-14).
- Files (17): hex envelopes of Parker's short nut (9 sizes) and long nut (8 sizes): hex across flats c, length l, a through hole at the tube OD. No internal thread, no 45° seat, no tube relief, because none is published; the thread size is in the file name only. The dimension the nut screws onto (male thread, 45° cone, flare diameter) is not published in a readable table, so no fitting body is drawn.
- Left out: flare diameters and the 45° flare envelope (SAE J533 / J512 values were not readable here; the 37° page lists J533 ranges), male and female connector bodies, elbows and tees (A, B, C columns of the catalogues could not be matched to the drawings), hose sizes, working pressures, and the Parker 41FX shorter nut. McMaster-Carr's category (linked) offers per-part STEP / IGES.

## Sizes

| dash size | tube OD, in (mm) | nut thread, UNF (major, mm) | Parker short nut 41FS: hex / length l, in | Parker long nut 41FL: hex / length l, in | Parker d, in | SC Fastening short rod nut: A / hex, in | SC Fastening long forged nut: A / hex, in |
|---|---|---|---|---|---|---|---|
| -2 | 1/8 (3.17) | 5/16-24 (major 7.94) | 3/8 / 0.50 | 3/8 / 0.75 | 0.133 | 0.50 / 0.37 | — |
| -3 | 3/16 (4.76) | 3/8-24 (major 9.52) | 7/16 / 0.62 | 7/16 / 0.81 | 0.195 | 0.62 / 0.43 | — |
| -4 | 1/4 (6.35) | 7/16-20 (major 11.11) | 9/16 / 0.75 | 9/16 / 0.94 | 0.257 | 0.75 / 0.56 | 0.94 / 0.62 |
| -5 | 5/16 (7.94) | 1/2-20 (major 12.70) | 5/8 / 0.88 | 5/8 / 1.12 | 0.320 | 0.88 / 0.62 | — |
| -6 | 3/8 (9.52) | 5/8-18 (major 15.88) | 3/4 / 1.00 | 3/4 / 1.31 | 0.382 | — | 1.06 / 0.81 |
| -8 | 1/2 (12.70) | 3/4-16 (major 19.05) | 7/8 / 1.12 | 7/8 / 1.62 | 0.507 | — | 1.19 / 0.94 |
| -10 | 5/8 (15.88) | 7/8-14 (major 22.22) | 1-1/16 / 1.31 | 1-1/16 / 1.88 | 0.632 | — | 1.44 / 1.06 |
| -12 | 3/4 (19.05) | 1-1/16-14 (major 26.99) | 1-1/4 / 1.50 | 1-1/4 / 2.19 | 0.757 | — | 1.75 / 1.31 |
| -14 | 7/8 (22.22) | 1-1/4-12 (major 31.75) | 1-1/2 / 1.62 | — | 0.882 | — | — |

## Where the files are

- Parker Hannifin (catalog 3501E, hosted on SlideShare): [45 degree flare fittings, pages H4-H10: 41FL long nut and 41FS / 41FX short nut: thread, hex c, d, length l](https://www.slideshare.net/tedtall/flare-fitting) — web — Publisher's page; dimensions are facts
- SC Fastening (JB-style catalogue): [SAE 45 flare short rod nut: tube OD, thread, A, hex](https://catalog.scfastening.com/compare/umbing-brass-fittings-sae-45-degree-flare-fittings/g-brass-fittings-sae-45-degree-flare-short-rod-nut) — web — Publisher's page; dimensions are facts
- SC Fastening (JB-style catalogue): [SAE 45 flare long forged nut: tube OD, thread, A, hex](https://catalog.scfastening.com/compare/umbing-brass-fittings-sae-45-degree-flare-fittings/brass-fittings-sae-45-degree-flare-long-forged-nut) — web — Publisher's page; dimensions are facts
- McMaster-Carr: [45-degree flared tube fittings (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/45-degree-flared-tube-fittings) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)

## Free STEP/STL (17 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/index.json

- flare-nut-short-41fs-2-tube-1-8in-5-16-24: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-2-tube-1-8in-5-16-24.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-2-tube-1-8in-5-16-24.stl) — SAE 45° flare short nut envelope (Parker 41FS-2): hex 3/8 in across flats × 0.50 in long, tube bore Ø3.17 mm (= 1/8 in tube OD); thread 5/16-24 is on the part but NOT drawn (internal thread depth and the 45° seat are not published); Parker's d column (0.133 in) is not used
- flare-nut-long-41fl-2-tube-1-8in-5-16-24: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-2-tube-1-8in-5-16-24.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-2-tube-1-8in-5-16-24.stl) — SAE 45° flare long nut envelope (Parker 41FL-2): hex 3/8 in across flats × 0.75 in long, tube bore Ø3.17 mm (= 1/8 in tube OD); thread 5/16-24 is on the part but NOT drawn
- flare-nut-short-41fs-3-tube-3-16in-3-8-24: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-3-tube-3-16in-3-8-24.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-3-tube-3-16in-3-8-24.stl) — SAE 45° flare short nut envelope (Parker 41FS-3): hex 7/16 in across flats × 0.62 in long, tube bore Ø4.76 mm (= 3/16 in tube OD); thread 3/8-24 is on the part but NOT drawn (internal thread depth and the 45° seat are not published); Parker's d column (0.195 in) is not used
- flare-nut-long-41fl-3-tube-3-16in-3-8-24: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-3-tube-3-16in-3-8-24.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-3-tube-3-16in-3-8-24.stl) — SAE 45° flare long nut envelope (Parker 41FL-3): hex 7/16 in across flats × 0.81 in long, tube bore Ø4.76 mm (= 3/16 in tube OD); thread 3/8-24 is on the part but NOT drawn
- flare-nut-short-41fs-4-tube-1-4in-7-16-20: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-4-tube-1-4in-7-16-20.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-4-tube-1-4in-7-16-20.stl) — SAE 45° flare short nut envelope (Parker 41FS-4): hex 9/16 in across flats × 0.75 in long, tube bore Ø6.35 mm (= 1/4 in tube OD); thread 7/16-20 is on the part but NOT drawn (internal thread depth and the 45° seat are not published); Parker's d column (0.257 in) is not used
- flare-nut-long-41fl-4-tube-1-4in-7-16-20: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-4-tube-1-4in-7-16-20.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-4-tube-1-4in-7-16-20.stl) — SAE 45° flare long nut envelope (Parker 41FL-4): hex 9/16 in across flats × 0.94 in long, tube bore Ø6.35 mm (= 1/4 in tube OD); thread 7/16-20 is on the part but NOT drawn
- flare-nut-short-41fs-5-tube-5-16in-1-2-20: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-5-tube-5-16in-1-2-20.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-5-tube-5-16in-1-2-20.stl) — SAE 45° flare short nut envelope (Parker 41FS-5): hex 5/8 in across flats × 0.88 in long, tube bore Ø7.94 mm (= 5/16 in tube OD); thread 1/2-20 is on the part but NOT drawn (internal thread depth and the 45° seat are not published); Parker's d column (0.320 in) is not used
- flare-nut-long-41fl-5-tube-5-16in-1-2-20: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-5-tube-5-16in-1-2-20.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-5-tube-5-16in-1-2-20.stl) — SAE 45° flare long nut envelope (Parker 41FL-5): hex 5/8 in across flats × 1.12 in long, tube bore Ø7.94 mm (= 5/16 in tube OD); thread 1/2-20 is on the part but NOT drawn
- flare-nut-short-41fs-6-tube-3-8in-5-8-18: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-6-tube-3-8in-5-8-18.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-6-tube-3-8in-5-8-18.stl) — SAE 45° flare short nut envelope (Parker 41FS-6): hex 3/4 in across flats × 1.00 in long, tube bore Ø9.52 mm (= 3/8 in tube OD); thread 5/8-18 is on the part but NOT drawn (internal thread depth and the 45° seat are not published); Parker's d column (0.382 in) is not used
- flare-nut-long-41fl-6-tube-3-8in-5-8-18: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-6-tube-3-8in-5-8-18.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-6-tube-3-8in-5-8-18.stl) — SAE 45° flare long nut envelope (Parker 41FL-6): hex 3/4 in across flats × 1.31 in long, tube bore Ø9.52 mm (= 3/8 in tube OD); thread 5/8-18 is on the part but NOT drawn
- flare-nut-short-41fs-8-tube-1-2in-3-4-16: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-8-tube-1-2in-3-4-16.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-8-tube-1-2in-3-4-16.stl) — SAE 45° flare short nut envelope (Parker 41FS-8): hex 7/8 in across flats × 1.12 in long, tube bore Ø12.70 mm (= 1/2 in tube OD); thread 3/4-16 is on the part but NOT drawn (internal thread depth and the 45° seat are not published); Parker's d column (0.507 in) is not used
- flare-nut-long-41fl-8-tube-1-2in-3-4-16: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-8-tube-1-2in-3-4-16.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-8-tube-1-2in-3-4-16.stl) — SAE 45° flare long nut envelope (Parker 41FL-8): hex 7/8 in across flats × 1.62 in long, tube bore Ø12.70 mm (= 1/2 in tube OD); thread 3/4-16 is on the part but NOT drawn
- flare-nut-short-41fs-10-tube-5-8in-7-8-14: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-10-tube-5-8in-7-8-14.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-10-tube-5-8in-7-8-14.stl) — SAE 45° flare short nut envelope (Parker 41FS-10): hex 1-1/16 in across flats × 1.31 in long, tube bore Ø15.88 mm (= 5/8 in tube OD); thread 7/8-14 is on the part but NOT drawn (internal thread depth and the 45° seat are not published); Parker's d column (0.632 in) is not used
- flare-nut-long-41fl-10-tube-5-8in-7-8-14: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-10-tube-5-8in-7-8-14.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-10-tube-5-8in-7-8-14.stl) — SAE 45° flare long nut envelope (Parker 41FL-10): hex 1-1/16 in across flats × 1.88 in long, tube bore Ø15.88 mm (= 5/8 in tube OD); thread 7/8-14 is on the part but NOT drawn
- flare-nut-short-41fs-12-tube-3-4in-1-1-16-14: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-12-tube-3-4in-1-1-16-14.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-12-tube-3-4in-1-1-16-14.stl) — SAE 45° flare short nut envelope (Parker 41FS-12): hex 1-1/4 in across flats × 1.50 in long, tube bore Ø19.05 mm (= 3/4 in tube OD); thread 1-1/16-14 is on the part but NOT drawn (internal thread depth and the 45° seat are not published); Parker's d column (0.757 in) is not used
- flare-nut-long-41fl-12-tube-3-4in-1-1-16-14: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-12-tube-3-4in-1-1-16-14.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-long-41fl-12-tube-3-4in-1-1-16-14.stl) — SAE 45° flare long nut envelope (Parker 41FL-12): hex 1-1/4 in across flats × 2.19 in long, tube bore Ø19.05 mm (= 3/4 in tube OD); thread 1-1/16-14 is on the part but NOT drawn
- flare-nut-short-41fs-14-tube-7-8in-1-1-4-12: [STEP](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-14-tube-7-8in-1-1-4-12.step) · [STL](https://xemstudio.com/files/hardware/sae-45-degree-flare-nuts-and-threads/flare-nut-short-41fs-14-tube-7-8in-1-1-4-12.stl) — SAE 45° flare short nut envelope (Parker 41FS-14): hex 1-1/2 in across flats × 1.62 in long, tube bore Ø22.22 mm (= 7/8 in tube OD); thread 1-1/4-12 is on the part but NOT drawn (internal thread depth and the 45° seat are not published); Parker's d column (0.882 in) is not used

## Questions

**What thread is a 1/4 in SAE 45° flare nut?**

7/16-20 UNF. 3/8 in tube is 5/8-18, 1/2 in tube is 3/4-16, 5/8 in is 7/8-14, 3/4 in is 1-1/16-14.

**What wrench fits a 3/8 in flare nut?**

Parker's 3/8 in tube nut (5/8-18) has a 3/4 in hex; SC Fastening's long forged nut for the same tube lists 0.81 in.

**Is a 45° flare the same as AN / JIC?**

No: AN and JIC seal on a 37° flare. The 1/4 in sizes share 7/16-20 but the seats do not interchange.

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