-10 JIC Fitting Size and Dimensions
A -10 JIC fitting is for 5/8 in tube and has a 7/8-14 UNF thread. Here are its measurements, look-alikes and published tightening values.
Last updated October 30, 2026. Reference values; verify against manufacturer specifications.
The -10 JIC is a common size on main pressure and return lines of mid-sized machines, such as loader circuits, power units and larger log splitters. It is the last JIC size with a UNF (fine) thread designation; from -12 up, JIC threads are 12-pitch UN. Its 7/8-14 thread is shared with two other fitting families and sits close to several pipe and metric threads. This page gives the full -10 dimensions, the look-alikes and the published tightening values.
-10 JIC at a glance
- Tube size: 5/8 in OD (15.88 mm). The dash number is the tube OD in sixteenths of an inch: 10/16 in = 5/8 in.
- Thread: 7/8-14 UNF: 0.8750 in major diameter, 14 threads per inch.
- Male OD: about 0.88 in (22.23 mm). Female ID: about 0.81 in (20.6 mm).
- Seat: 37° flare, metal-to-metal.
-10 JIC fitting dimensions
| Dimension | Inch | Metric |
|---|---|---|
| Tube OD | 5/8 in (0.625 in) | 15.88 mm |
| Thread | 7/8-14 UNF | pitch 1.814 mm |
| Threads per inch | 14 | 1.814 mm per thread |
| Male thread OD | 0.8750 in | 22.23 mm |
| Female thread ID (approx.) | 0.81 in | 20.6 mm |
| Seat angle | 37° from centreline (74° included) | same |
| Hex size | Varies by maker and part | check the catalog |
Thread and tube sizes per SAE J514 as published by Parker and Eaton. Female ID is the approximate value in the Eaton and McGill identification guides. Metric values are converted from inch at 25.4 mm/in. Hex sizes are not standardised across makers, so they are not listed.
"-10" describes the 5/8 in tube, not the 7/8 in thread. The female thread ID is a measured approximation, and published values for -10 differ slightly: 0.81 in in the guides used here, 0.80 in in others. Either reading points to -10, because the next sizes are a long way off (about 0.69 in for -8 and 0.98 in for -12).
How to confirm a -10 JIC fitting
- Check the seat. A male -10 JIC has a convex cone nose. If you have a seat gauge, it should sit flush at 37°.
- Measure the thread. A male should read close to 0.88 in (22.2 mm). A female should read about 0.81 in (20.6 mm) across the inner crests. See how to measure JIC fittings.
- Check the pitch. The 14 TPI leaf of an inch thread gauge should sit flush. The pitch is 1.81 mm, which is not a standard metric pitch, so every leaf of a metric gauge will rock.
- Rule out look-alikes using the table below, or enter your numbers in the finder on the JIC identification page.
Fittings that look like -10 JIC
The 7/8-14 thread is used on -10 JIC, -10 SAE 45° flare and -10 ORB fittings, so the seat is the only reliable test between them. Pipe, BSP, ORFS and metric threads also come within about 1 mm:
| Fitting | Thread | OD (in / mm) | TPI or pitch | How to tell |
|---|---|---|---|---|
| -10 SAE 45° flare (SAE J512) | 7/8-14 (same) | 0.88 / 22.23 | 14 TPI | 45° cone instead of 37° |
| -10 ORB (SAE J1926) | 7/8-14 (same) | 0.88 / 22.23 | 14 TPI | O-ring under the hex, no cone |
| 1/2 NPT | 1/2-14 NPT | about 0.84 / 21.3 | 14 TPI | Same TPI; tapered thread, no seat |
| G5/8 BSP | 5/8-14 BSP | 22.91 mm major; about 0.88 in measured | 14 TPI | 55° thread; same TPI; usually a 60° cone or flat seat |
| -8 ORFS (SAE J1453) | 13/16-16 | 0.81 / 20.64 | 16 TPI | Flat face with an O-ring groove; finer pitch |
| M22x1.5 metric | M22x1.5 | 0.87 / 22.0 | 1.5 mm (about 16.9 TPI) | Pitch; usually a 24° or 30° seat |
Look-alike threads from the Eaton and McGill thread identification guides, which agree on these sizes; metric threads are nominal.
The -10 size has more same-pitch look-alikes than any other JIC size. 1/2 NPT and G5/8 BSP both have 14 threads per inch, so a 14 TPI gauge leaf will sit on all three. For NPT, look for the taper. For BSP, check the thread angle with a 55° gauge leaf and the seat. M22x1.5 is within about 0.2 mm of the -10 JIC diameter, but its pitch is clearly finer. Comparisons in detail: JIC vs NPT, JIC vs BSP, JIC vs ORFS, JIC metric conversion.
Torque and flats for -10 JIC
Parker recommends tightening steel JIC fittings by flats from wrench resistance (FFWR) and gives torque as a reference. Published torque ranges for the same size differ between sources:
| Source | Value | Notes |
|---|---|---|
| Parker Catalog 4400, swivel nut | 1-1/2 flats; reference 60 ft-lb (81 N·m) | FFWR is the recommended method |
| Tameson JIC assembly guide, flared tube nut / swivel nut | 1-1/2 flats / 1-1/2 flats | Same rotation for tube and swivel |
| Hose and Fittings assembly chart, tube / swivel | 1-1/2 flats / 1 flat; 55–65 ft-lb | Fewer swivel flats than Parker |
| SAE J514 range (as published by distributors) | 57–63 ft-lb (77–85 N·m) | Torque range, steel |
Bring the nut to finger-tight, then wrench-tight until you feel resistance. Mark the nut and the fitting, and turn the nut the stated number of flats; one flat is 60°. The full table, with material adjustments, is on the JIC torque chart.
-10 JIC next to its neighbouring sizes
There is no -9 JIC, so the neighbours are -8 (3/4-16) and -12 (1-1/16-12). They differ in both diameter and pitch, which makes -10 one of the easier sizes to confirm once you have ruled out the same-thread families.
| Dash | Tube OD (in) | Thread | Male OD (mm) | Female ID (mm, approx.) |
|---|---|---|---|---|
| -8 | 1/2 | 3/4-16 | 19.05 | 17.5 |
| -10 | 5/8 | 7/8-14 | 22.23 | 20.6 |
| -12 | 3/4 | 1-1/16-12 | 26.99 | 24.9 |
Hose, tube and adapters
On most hydraulic hose, a -10 dash number means a 5/8 in inside diameter. SAE 100R5 hose follows tube sizing instead, so a -10 R5 hose has a 1/2 in bore (see JIC hose end sizes). To connect a -10 JIC line to a different port, use an adapter with a male -10 JIC end and the matching port end, for example -10 ORB or 1/2 NPT. Published working pressures for this size are on the JIC pressure rating page, and the full range of sizes is on the JIC fitting size chart.
Other single-size pages: -4 JIC fitting size, -6 JIC fitting size, -8 JIC fitting size, -12 JIC fitting size, -16 JIC fitting size. All sizes in one table: the JIC dash size chart. To check which half of a joint you are holding, see male vs female JIC fittings.
References
SAE J514 dimensions as published by Parker and Eaton; Eaton Thread Identification Guide; McGill Hose thread identification guide; Parker Catalog 4400 assembly methods. Values are reference only.
Frequently asked questions
What thread is a -10 JIC fitting?
7/8-14 UNF: 7/8 in (22.23 mm) major diameter with 14 threads per inch.
What tube size is -10 JIC?
5/8 in OD tube (15.88 mm). The dash number is the tube OD in sixteenths of an inch: 10/16 = 5/8.
Is -10 JIC the same as 5/8 JIC?
Yes. "5/8 JIC" refers to the tube size. The thread is 7/8-14.
Can a -10 JIC thread into a 1/2 NPT port?
Both have 14 threads per inch and similar diameters, so it may start, but it will not seal. NPT is tapered and has no 37° seat. Use a -10 JIC to 1/2 NPT adapter.
How much torque does a -10 JIC need?
Parker gives 1-1/2 flats from wrench resistance for a steel swivel, with a reference torque of 60 ft-lb (81 N·m). Published SAE J514 ranges list 57–63 ft-lb. Follow your fitting maker's instructions.