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SAE J1926 / ISO 11926 O-ring boss ports (ORB), dash -2 to -32: thread, spotface, depths, O-ring
What are the thread, spotface diameter, port depth and O-ring of an SAE -6 or -8 O-ring boss port? · Standard part · basis: Parker Tube Fittings Division catalog 4300 table S23 (J1926-1 / ISO 11926-1), cross-checked against the older Parker edition and the ISO 11926-1:1995 sample pages; AS568-9xx O-ring sizes from Apple Rubber; numbers only
Also called: sae 8 orb port dimensions, -6 orb port spotface, sae j1926 port dimensions, 3/4-16 o-ring boss port depth, sae -10 orb o-ring size, orb o-ring 3-908, iso 11926-1 port, o-ring boss port tap drill depth, 7/16-20 orb port dimensions, 9/16-18 port spotface diameter, orb port d5 bore, sae -12 port 1-1/16-12, orb vs orfs, orb port chamfer angle 15 degrees
Exact dimensions. True size, with no tolerance added.
- sizes
- 13 in table
Notes
- SAE J1926-1 (identical in scope to ISO 11926-1) is the straight-thread O-ring boss port: a UN / UNF thread with a flat spotfaced face and an O-ring that seals in the port's conical seat. The table is Parker Tube Fittings Division catalog 4300, General Technical, PDF version 11 (6/2025), table S23, with the page's own column letters: d2 diameter, d3 diameter min (a connecting-hole reference), d4 diameter min, d5 diameter +0.13 / −0.00, L1 +0.4 / −0.00, L2 min, L3 max, L4 full thread min, Z ±1° (dimensions in mm). Parker's footnotes: if the boss face is on a machined surface, d2 and L3 do not apply provided a corner radius of R0.2 is kept; d5 must be concentric with the thread pitch diameter within 0.1 mm FIM and free of longitudinal and spiral tool marks (annular marks up to 2.5 µm are permitted); tap drill depths (L2) assume a bottoming tap, with a standard tap increase them; L3 is the maximum recommended spotface depth, which leaves enough wrench grip; the standard hydraulic O-ring is 90 durometer nitrile.
- Cross-checks. An older Parker 4300 edition (table U18, page U26) prints the same 13 rows of values; its column headings read differently in the text we could read (d4 and d5 tolerances attached to other columns), so the 2025 headings are used. The ISO 11926-1:1995 sample pages (iTeh, OCR text with garbled headings and some wrong digits) give the same thread sizes and d2, d4 values for every size from 3/8-24 to 2 1/2-12, and slightly different figures in the two bore columns that correspond to Parker's d3 and d5 (for example 3.15 vs 3.2, 4.5 vs 4.4, 12.45 vs 12.4, 20.65 vs 20.6, 65.75 vs 65.7); the ISO scope says the part covers ports with ISO 725 inch threads for the stud ends of ISO 11926-2 and -3, with pressures up to 63 MPa (non-adjustable) or 40 MPa (adjustable) depending on size, and that ISO 6149 is to be used for new hydraulic designs. The ISO sample's footnotes call d2 the minimum recommended spotface diameter and the last length the maximum recommended spotface depth.
- O-rings: Parker 3-9xx boss O-rings are AS568 -9xx sizes; ID and W (inches) are from Apple Rubber's boss-gasket table (ID tolerances ± .005 to ± .018, W ± .003 or .004); the mm figures are Xem's conversion at 25.4. The tube OD columns are Parker's: any boss can be used for a tube size depending on other design criteria. SAE dash -1 (AS568 -901, 3/32 in tube) is in Apple's O-ring table but not in Parker's port table.
- Left out, no file: the shape between the spotface and the thread (a cone at the angle Z from d4 down to the d5 bore, then the thread run-out) is drawn in the standard's figure, which did not come through in any text read; building a cavity solid from d4, d5, L1 and Z alone would be a guess, so only the table is published. Port gauges can be made from the d5 bore and d2 spotface once the figure is in hand. Related standards on other pages: AN / JIC 37° flare ends use the same threads (an-jic-37-degree-flare-fittings); the O-ring face seal (ORFS) is orfs-sae-j1453-o-ring-face-seal-ends.
- Maker CAD: Parker's catalog pages are linked (maker source for the numbers). McMaster-Carr sells O-ring boss adapters with per-part STEP; no per-part link was read, so none is given.
SAE J1926 / ISO 11926 O-ring boss ports (ORB), dash -2 to -32… size chart
| SAE dash | thread | tube OD (in) | tube OD (mm) | d2 dia (spotface) | d3 dia min | d4 dia min | d5 dia +0.13/−0 | L1 +0.4/−0 | L2 min (tap drill depth) | L3 max (spotface depth) | L4 min (full thread) | Z ±1° | Parker O-ring | O-ring ID × W |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| -2 | 5/16-24 UNF-2B | 1/8 | — | 17 | 1.6 | 11 | 9.1 | 1.9 | 12 | 1.6 | 10 | 12° | 3-902 | .239 × .064 in (6.07 × 1.63 mm, converted) |
| -3 | 3/8-24 UNF-2B | 3/16 | 4 | 19 | 3.2 | 13 | 10.7 | 1.9 | 12 | 1.6 | 10 | 12° | 3-903 | .301 × .064 in (7.65 × 1.63 mm, converted) |
| -4 | 7/16-20 UNF-2B | 1/4 | 6 | 21 | 4.4 | 15 | 12.4 | 2.4 | 14 | 1.6 | 11.5 | 12° | 3-904 | .351 × .072 in (8.92 × 1.83 mm, converted) |
| -5 | 1/2-20 UNF-2B | 5/16 | 8 | 23 | 6 | 16 | 14 | 2.4 | 14 | 1.6 | 11.5 | 12° | 3-905 | .414 × .072 in (10.52 × 1.83 mm, converted) |
| -6 | 9/16-18 UNF-2B | 3/8 | 10 | 25 | 7.5 | 18 | 15.6 | 2.5 | 15.5 | 1.6 | 12.7 | 12° | 3-906 | .468 × .078 in (11.89 × 1.98 mm, converted) |
| -8 | 3/4-16 UNF-2B | 1/2 | 12 | 30 | 10 | 22 | 20.6 | 2.5 | 17.5 | 2.4 | 14.3 | 15° | 3-908 | .644 × .087 in (16.36 × 2.21 mm, converted) |
| -10 | 7/8-14 UNF-2B | 5/8 | 14, 15, 16 | 34 | 12.5 | 26 | 23.9 | 2.5 | 20 | 2.4 | 16.7 | 15° | 3-910 | .755 × .097 in (19.18 × 2.46 mm, converted) |
| -12 | 1 1/16-12 UN-2B | 3/4 | 18, 20 | 41 | 16 | 32 | 29.2 | 3.3 | 23 | 2.4 | 19 | 15° | 3-912 | .924 × .116 in (23.47 × 2.95 mm, converted) |
| -14 | 1 3/16-12 UN-2B | 7/8 | 22 | 45 | 18 | 35 | 32.3 | 3.3 | 23 | 2.4 | 19 | 15° | 3-914 | 1.047 × .116 in (26.59 × 2.95 mm, converted) |
| -16 | 1 5/16-12 UN-2B | 1 | 25, 28 | 49 | 21 | 38 | 35.5 | 3.3 | 23 | 3.2 | 19 | 15° | 3-916 | 1.171 × .116 in (29.74 × 2.95 mm, converted) |
| -20 | 1 5/8-12 UN-2B | 1 1/4 | 30, 32, 35 | 58 | 27 | 48 | 43.5 | 3.3 | 23 | 3.2 | 19 | 15° | 3-920 | 1.475 × .118 in (37.47 × 3.00 mm, converted) |
| -24 | 1 7/8-12 UN-2B | 1 1/2 | 38, 42 | 65 | 33 | 54 | 49.8 | 3.3 | 23 | 3.2 | 19 | 15° | 3-924 | 1.720 × .118 in (43.69 × 3.00 mm, converted) |
| -32 | 2 1/2-12 UN-2B | 2 | 50 | 88 | 45 | 70 | 65.7 | 3.3 | 23 | 3.2 | 19 | 15° | 3-932 | 2.337 × .118 in (59.36 × 3.00 mm, converted) |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Parker Tube Fittings Division | Catalog 4300 General Technical (PDF version 11, 6/2025), table S23: Port detail, SAE J1926-1 (ISO 11926-1) | web | Maker catalog page; numbers only |
| Parker Tube Fittings Division (older 4300 edition, page U26) | Table U18: Port detail, SAE J1926-1 (ISO 11926-1), conforms to MS16142 | web | Maker catalog page; numbers only |
| ISO (iTeh sample pages) | ISO 11926-1:1995 Table 1 (OCR text; headings and some digits garbled), scope and footnotes | web | Standards-body sample pages; numbers only |
| Apple Rubber | Standard O-rings for boss gaskets for straight thread tube fittings, AS568-901 to -932: tube size, ID, W with tolerances | web | Maker sheet; numbers only |
Xem scan
File coming
No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.
https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.Plain text: sheet.txt · JSON: /api/geometry?object=sae-j1926-iso-11926-o-ring-boss-ports
Fits with
Questions
What is the spotface diameter of an SAE -8 ORB port?
Parker's table S23 prints d2 = 30 mm for the -8 port (3/4-16 UNF-2B); if the face is a machined surface d2 and L3 do not apply with an R0.2 corner radius.
What O-ring goes in an SAE -6 O-ring boss port?
AS568 -906 (Parker 3-906): ID .468 in, cross-section .078 in (Apple Rubber), for the 9/16-18 UNF-2B port.
How deep is the tap drill for an SAE -8 O-ring boss port?
L2 min is 17.5 mm with a bottoming tap (Parker); the minimum full thread length L4 is 14.3 mm. With a standard tap the tap drill must be deeper.
Is a JIC fitting the same thread as an SAE O-ring boss port?
The thread sizes are the same (9/16-18 for -6, 3/4-16 for -8, and so on), but a JIC -8 seals on a 37° flare and an O-ring boss port seals with an O-ring: they do not interchange.