-12 JIC Fitting Size and Dimensions
A -12 JIC fitting is for 3/4 in tube and has a 1-1/16-12 UN thread. Here are its measurements, look-alikes and published tightening values.
Last updated October 30, 2026. Reference values; verify against manufacturer specifications.
The -12 JIC is the first of the large sizes. It appears on pump suction and pressure lines, return lines and main circuits on tractors, excavators and industrial power units. It is also the first JIC size with a 12-pitch UN thread instead of a UNF thread, and from here up every JIC size has 12 threads per inch. That makes the caliper reading more important than the pitch gauge. This page gives the full -12 dimensions, the look-alikes and the published tightening values.
-12 JIC at a glance
- Tube size: 3/4 in OD (19.05 mm). The dash number is the tube OD in sixteenths of an inch: 12/16 in = 3/4 in.
- Thread: 1-1/16-12 UN: 1.0625 in major diameter, 12 threads per inch.
- Male OD: about 1.06 in (26.99 mm). Female ID: about 0.98 in (24.9 mm).
- Seat: 37° flare, metal-to-metal.
-12 JIC fitting dimensions
| Dimension | Inch | Metric |
|---|---|---|
| Tube OD | 3/4 in (0.750 in) | 19.05 mm |
| Thread | 1-1/16-12 UN | pitch 2.117 mm |
| Threads per inch | 12 | 2.117 mm per thread |
| Male thread OD | 1.0625 in | 26.99 mm |
| Female thread ID (approx.) | 0.98 in | 24.9 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.
"-12" describes the 3/4 in tube, not the thread. The -12 thread is 1-1/16 in across, which is also the thread of a -12 SAE 45° flare, but with a different pitch (see below). Because -12, -14 and -16 all have 12 TPI, measure the diameter carefully: 1.06 in for -12, 1.19 in for -14, 1.31 in for -16.
How to confirm a -12 JIC fitting
- Check the seat. A male -12 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 1.06 in (27.0 mm). A female should read about 0.98 in (24.9 mm) across the inner crests. See how to measure JIC fittings.
- Check the pitch. The 12 TPI leaf of an inch thread gauge should sit flush. The pitch is 2.12 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 -12 JIC
The 1-1/16-12 thread is used on -12 JIC and -12 ORB fittings. The -12 SAE 45° flare is the odd one out: it has the same diameter but 14 threads per inch, so it may start on a -12 JIC thread and then bind. Pipe, BSP and ORFS threads also come close:
| Fitting | Thread | OD (in / mm) | TPI or pitch | How to tell |
|---|---|---|---|---|
| -12 ORB (SAE J1926) | 1-1/16-12 (same) | 1.06 / 26.99 | 12 TPI | O-ring under the hex, no cone |
| -12 SAE 45° flare (SAE J512) | 1-1/16-14 | 1.06 / 26.99 | 14 TPI | Finer pitch and a 45° cone |
| -10 ORFS (SAE J1453) | 1-14 | 1.00 / 25.40 | 14 TPI | Flat face with an O-ring groove; smaller |
| G3/4 BSP | 3/4-14 BSP | about 1.04 / 26.44 | 14 TPI | 55° thread, finer pitch |
| 3/4 NPT | 3/4-14 NPT | about 1.05 / 26.7 | 14 TPI | Tapered thread, no seat |
Look-alike threads from the Eaton and McGill thread identification guides, which agree on these sizes; metric threads are nominal.
Every look-alike in the table has 14 TPI, while -12 JIC has 12 TPI. A 12 TPI gauge leaf is therefore the fastest way to separate -12 JIC from all of them except -12 ORB, which needs a look at the end of the fitting. Comparisons in detail: JIC vs SAE 45°, JIC vs ORB, JIC vs BSP, JIC vs NPT.
Torque and flats for -12 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 | 1-1/4 flats; reference 84 ft-lb (114 N·m) | FFWR is the recommended method |
| Tameson JIC assembly guide, flared tube nut / swivel nut | 1-1/2 flats / 1-1/4 flats | Tube nuts take more rotation than swivels |
| Hose and Fittings assembly chart, tube / swivel | 1-1/4 flats / 1 flat; 80–90 ft-lb | Fewer flats than Tameson |
| SAE J514 range (as published by distributors) | 79–88 ft-lb (107–119 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.
-12 JIC next to its neighbouring sizes
The -14 JIC (1-3/16-12) is less common than -12 and -16, but it exists and has the same 12 TPI. A -12 and a -14 differ by about 3.2 mm in diameter, so a caliper separates them easily; a pitch gauge does not.
| Dash | Tube OD (in) | Thread | Male OD (mm) | Female ID (mm, approx.) |
|---|---|---|---|---|
| -10 | 5/8 | 7/8-14 | 22.23 | 20.6 |
| -12 | 3/4 | 1-1/16-12 | 26.99 | 24.9 |
| -14 | 7/8 | 1-3/16-12 | 30.16 | 27.9 |
Hose, tube and adapters
On most hydraulic hose, a -12 dash number means a 3/4 in inside diameter. SAE 100R5 hose follows tube sizing instead, so a -12 R5 hose has a 5/8 in bore (see JIC hose end sizes). To connect a -12 JIC line to a different port, use an adapter with a male -12 JIC end and the matching port end, for example -12 ORB or 3/4 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, -10 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 -12 JIC fitting?
1-1/16-12 UN: 1-1/16 in (26.99 mm) major diameter with 12 threads per inch.
What tube size is -12 JIC?
3/4 in OD tube (19.05 mm). The dash number is the tube OD in sixteenths of an inch: 12/16 = 3/4.
Is -12 JIC the same as -12 SAE 45°?
No. Both are 1-1/16 in across, but JIC has 12 threads per inch and SAE 45° has 14, and the seat angles differ. They are not interchangeable.
Is -12 JIC UNF or UN?
UN. JIC threads are UNF up to -10, and 12-pitch UN from -12 upward.
How much torque does a -12 JIC need?
Parker gives 1-1/4 flats from wrench resistance for a steel swivel, with a reference torque of 84 ft-lb (114 N·m). Published SAE J514 ranges list 79–88 ft-lb. Follow your fitting maker's instructions.