# Hydraulic quick couplers: ISO 16028 flat-face and ISO 7241-A / B plug diameters (J) by size, 1/4 to 1 in

> What is the plug diameter of an ISO 16028 flat-face or ISO 7241-A hydraulic quick coupler, by size?

- Category: Tri-clamp & pipe › Pipe, tube & threads
- Kind: Standard part
- Basis: OMFB's quick-coupling tables (J), Stucchi's flat face A / FIRG / FL / FIRG Q tables (J), Flowfit's ISO 16028 table (Ød) and Parker's WK-MK112 catalog (series and threads); numbers only
- Page: https://xemstudio.com/objects/hydraulic-quick-couplers-iso-16028-iso-7241/ · JSON: https://xemstudio.com/api/geometry?object=hydraulic-quick-couplers-iso-16028-iso-7241 · Plain text: https://xemstudio.com/objects/hydraulic-quick-couplers-iso-16028-iso-7241/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
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**Exact dimensions.** True size, with no tolerance added.

## Notes

- Quick-coupler families: ISO 16028 is the flat-face coupling (the 'flush face' coupler on skid-steer and ag hydraulics: a flat plug nose, no poppet to trap dirt); ISO 7241 (parts 1 and 2; series A and B) is the ball-lock poppet coupling; the numbers here are the male plug (nipple) body diameter that the coupler's ball lock grips, because that is the interface diameter a designer needs. Plug diameter is the letter J in OMFB's and Stucchi's tables (OMFB's text explains only J, as 'male Ø for ball-lock types'; Stucchi's sheet does not define its letters) and Ød on male rows in Flowfit's table (letters not defined there). The three sources agree on the same plug diameters (within 0.05 mm: 16.1 / 16.15, 19.7 / 19.75, 24.5, 27, 30 / 29.95, 36), so J and Ød are the same dimension.
- ISO 16028 rows: 1/4 in (ISO size 6.3) 16.1 mm, 3/8 in (10) 19.7, 1/2 in (12.5) 24.5, 5/8 in (16) 27.0, 3/4 in (19) 30.0, 1 in (25) 36.0 (Stucchi's Flat Face 'A' series, whose sheet says it is in accordance with ISO 16028). Sizes 1/8 (11.6), 1 1/4 (44.0), 1 1/2 (57.0) and 2 in (73.0) are in Stucchi's tables with no ISO size printed, and are not claimed as ISO 16028 sizes here. Naming differs by maker: Stucchi calls the 3/4 in size ISO size 19, OMFB's dash 12 is DN 20 and Flowfit's is DN 19; the plug diameter is the same (30 / 29.95 mm). OMFB's note says only the G 1/2 size of one series is compatible with ISO 7241-A.
- ISO 7241 rows: J from OMFB's MB series A and B tables (and Stucchi's BIR series for A, which prints the same J for dash 06 to 20). The page prints no J for ISO 7241 in other makers' series, and no ISO 7241 plug groove, lanyard groove, overall length or hex values (only 'HEX. B / C' as drawn). Parker's WK-MK112 catalog lists its 60 series (ISO 7241 series B), 6600 series (ISO 7241 series A) and FEM / FEC series (ISO 16028) body sizes 1/8 to 1 in with NPT, ORB (SAE O-ring boss) and BSPP threads but no interface dimensions, so it is cited for what threads each series comes in, not for diameters.
- Left out, no file: a plug body is not just a diameter: the ball-lock groove, the poppet or flat-face nose, and the lengths are drawn in the standard and in makers' dimensioned drawings, none of which came through as numbers; an invented plug would not be a standard part. The tables give the diameters to bore a socket or a hole around. Overall lengths per maker series (Stucchi B to I letters, OMFB B to F, Flowfit C) are published by the makers and not mixed here because their letters are undefined and the series differ.
- Not the same as air couplers: for pneumatic plug profiles (industrial M / H / G, Tru-Flate, ARO, European) see air-quick-coupler-plug-profiles; for cam-and-groove hose couplings see camlock-couplings. McMaster-Carr sells ISO A series (ISO 7241-A) hydraulic couplings with per-part STEP; its category page is linked, not copied. Stucchi, OMFB, Parker and Flowfit catalogs are linked as the maker sources.

## Sizes

| standard | size | ISO size / DN | plug Ø J (Stucchi Flat Face A, mm) | Flowfit Ød (mm) | OMFB J (mm) |
|---|---|---|---|---|---|
| ISO 16028 flat face | 1/8 in | — | 11.6 | — | — |
| ISO 16028 flat face | 1/4 in | 6.3 | 16.1 | 16.15 (DN 6.3) | — |
| ISO 16028 flat face | 3/8 in | 10.0 | 19.7 | 19.75 (DN 10) | 19.7 (dash 06, DN 10: Stucchi FIRG, DNP PLT1, Faster FFH, MB F) |
| ISO 16028 flat face | 1/2 in | 12.5 | 24.5 | 24.5 (DN 12.5) | 24.5 (dash 08, DN 12.5) |
| ISO 16028 flat face | 5/8 in | 16.0 | 27.0 | 27 (DN 16) | 27 (dash 10, DN 16) |
| ISO 16028 flat face | 3/4 in | 19.0 | 30.0 | 29.95 (DN 19) | 30 (dash 12, DN 20) |
| ISO 16028 flat face | 1 in | 25.0 | 36.0 | 36 (DN 25) | 36 (dash 16, DN 25) |
| ISO 16028 flat face | 1 1/4 in | — | 44.0 | — | — |
| ISO 16028 flat face | 1 1/2 in | — | 57.0 | — | 57 (dash 24, DN 37.5: Stucchi FIRG) |
| ISO 16028 flat face | 2 in | — | 73.0 | — | — |
| ISO 7241-1 A (OMFB MB series A; Stucchi BIR) | 3/8 in (dash 06) | 10 mm | 17.3 | — | — |
| ISO 7241-1 A | 1/2 in (dash 08) | 12.5 mm | 20.5 | — | — |
| ISO 7241-1 A | 3/4 in (dash 12) | 20 mm | 29.1 | — | — |
| ISO 7241-1 A | 1 in (dash 16) | 25 mm | 34.3 | — | — |
| ISO 7241-1 A | 1 1/4 in (dash 20) | 31.5 mm | 45 | — | — |
| ISO 7241-1 A | 1 1/2 in (dash 24) | 37.5 mm | 55 (OMFB MB A only) | — | — |
| ISO 7241-1 B (OMFB MB series B) | 3/8 in (dash 06) | 10 mm | 19.1 | — | — |
| ISO 7241-1 B | 1/2 in (dash 08) | 12.5 mm | 23.5 | — | — |
| ISO 7241-1 B | 3/4 in (dash 12) | 20 mm | 31.4 | — | — |
| ISO 7241-1 B | 1 in (dash 16) | 25 mm | 37.7 | — | — |

## Where the files are

- OMFB (quick couplings catalogue): [MB series A / B (ISO 7241-1) and ISO 16028 flat face: dash, DN, thread, pressure, J, B to F (and Stucchi, DNP, Faster, MB F series tables)](https://www.omfb.com/catalog/media/ARXIVAR_WEB/99711900010.pdf) — web — Maker catalogue; numbers only. Only J is defined in the text
- Stucchi (quick disconnect catalog, hosted by Hydraquip): [Flat face A, FIRG, FL and FIRG Q series (ISO 16028): body size, port, B to J, ISO size, weight](https://www.hydraquip.com/wp-content/uploads/2018/02/stucchi-quick-disconnect-catalog.pdf) — web — Maker catalogue; numbers only. The letters are not defined in the text; B and C are drawn as hex sizes
- Flowfit: [ISO 16028 flat face couplings (carbon steel, metric): DN, PN, ØA, C, Ød, ch, ØM](https://www.flowfitonline.com/uploads/PDFproducts/03-10-flat-face-21-6.pdf) — web — Maker catalogue; numbers only. The page does not define its letters
- Parker (Hydraulic quick coupler catalog WK-MK112): [60 Series ISO 7241 series B, 6600 Series ISO 7241 series A, FEM / FEC ISO 16028: body sizes and threads](https://www.parker.com/content/dam/Parker-com/Literature/Canada/Canada-Support-Assets/WK-MK112-Hydraulic-Quick-Coupler-Sept-2017.pdf) — web — Maker catalogue; numbers only
- McMaster-Carr: [ISO A series couplings (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/iso-a-series-couplings) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)

## Questions

**What is the plug diameter of a 1/2 in ISO 16028 flat-face coupler?**

24.5 mm: Stucchi's Flat Face A series J, Flowfit's Ød (DN 12.5) and OMFB's J (dash 08) all print 24.5.

**What is the difference between ISO 7241-A and ISO 7241-B?**

They are different plug interfaces: OMFB's 3/8 in plug is 17.3 mm for series A and 19.1 mm for series B (1/2 in: 20.5 vs 23.5), so A and B couplers do not interchange.

**Is a 3/4 in flat-face coupler DN 19 or DN 20?**

Makers differ: Stucchi prints ISO size 19.0, Flowfit DN 19, OMFB DN 20 for the same 29.95 to 30 mm plug.

## Fits with

- [Air quick-coupler plug profiles: industrial M / H / G, Tru-Flate T, ARO A, European 7.2, Japanese, Lincoln, Schrader (tip diameter and length)](https://xemstudio.com/objects/air-quick-coupler-plug-profiles/)
- [Camlock (cam and groove) couplings: types A, B, C, D, E, F, DC, DP, 1/2 to 4 in sizes, adapter flange diameter](https://xemstudio.com/objects/camlock-couplings/)
- [SAE J1926 / ISO 11926 O-ring boss ports (ORB), dash -2 to -32: thread, spotface, depths, O-ring](https://xemstudio.com/objects/sae-j1926-iso-11926-o-ring-boss-ports/)
- [AN and JIC 37° flare fittings: dash sizes -3 to -20, thread, tube OD, hose ID, flare diameter](https://xemstudio.com/objects/an-jic-37-degree-flare-fittings/)
- [ORFS O-ring face seal fittings (SAE J1453), dash -4 to -24: thread, tube OD, O-ring size, nut hex + lock-nut envelopes](https://xemstudio.com/objects/orfs-sae-j1453-o-ring-face-seal-ends/)
- [ISO 1179 / BSPP (G thread) ports with O-ring or bonded seal: D3, D4, O-ring size, Dowty bonded-seal ID, OD, thickness](https://xemstudio.com/objects/iso-1179-bspp-ports-and-bonded-seals/)