-16 JIC Fitting Size and Dimensions
A -16 JIC fitting is for 1 in tube and has a 1-5/16-12 UN thread. Here are its measurements, look-alikes and published tightening values.
Last updated October 30, 2026. Reference values; verify against manufacturer specifications.
The -16 JIC is the largest size in everyday use on mobile equipment, typically on pump suction and main return lines. At this size the fittings are heavy, the published torque values are high, and the look-alikes include a British pipe thread that is almost the same diameter. This page gives the full -16 dimensions, the fittings it is most often confused with, and the published tightening values.
-16 JIC at a glance
- Tube size: 1 in OD (25.40 mm). The dash number is the tube OD in sixteenths of an inch: 16/16 in = 1 in.
- Thread: 1-5/16-12 UN: 1.3125 in major diameter, 12 threads per inch.
- Male OD: about 1.31 in (33.34 mm). Female ID: about 1.23 in (31.2 mm).
- Seat: 37° flare, metal-to-metal.
-16 JIC fitting dimensions
| Dimension | Inch | Metric |
|---|---|---|
| Tube OD | 1 in (1.000 in) | 25.40 mm |
| Thread | 1-5/16-12 UN | pitch 2.117 mm |
| Threads per inch | 12 | 2.117 mm per thread |
| Male thread OD | 1.3125 in | 33.34 mm |
| Female thread ID (approx.) | 1.23 in | 31.2 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.
"-16" describes the 1 in tube; the thread is 1-5/16 in across. The female thread ID is a measured approximation, and published values for -16 range from about 1.21 to 1.23 in. Any of these points to -16 rather than -14 (about 1.10 in) or -20 (about 1.54 in).
How to confirm a -16 JIC fitting
- Check the seat. A male -16 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 1.31 in (33.3 mm). A female should read about 1.23 in (31.2 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 -16 JIC
The 1-5/16-12 thread is used on -16 JIC and -16 ORB fittings. The -16 SAE 45° flare has a larger thread (1-3/8-12), and several pipe, BSP and metric threads sit within about 1 mm of the JIC diameter:
| Fitting | Thread | OD (in / mm) | TPI or pitch | How to tell |
|---|---|---|---|---|
| -16 ORB (SAE J1926) | 1-5/16-12 (same) | 1.31 / 33.34 | 12 TPI | O-ring under the hex, no cone |
| -16 SAE 45° flare (SAE J512) | 1-3/8-12 | 1.38 / 34.93 | 12 TPI | Same pitch; about 1.6 mm larger; 45° cone |
| -16 ORFS (SAE J1453) | 1-7/16-12 | 1.44 / 36.51 | 12 TPI | Same pitch; flat face with an O-ring groove |
| G1 BSP | 1-11 BSP | 33.25 mm major; about 1.30 in measured | 11 TPI | 55° thread; nearly the same diameter |
| 1 NPT | 1-11-1/2 NPT | about 1.32 / 33.5 | 11-1/2 TPI | Tapered thread, no seat |
| M33x1.5 metric | M33x1.5 | 1.30 / 33.0 | 1.5 mm (about 16.9 TPI) | Much finer pitch; 24° or 30° seat |
Look-alike threads from the Eaton and McGill thread identification guides, which agree on these sizes; metric threads are nominal.
G1 BSP is the closest match: its major diameter is within about 0.1 mm of -16 JIC, and 11 TPI is close to 12 TPI over a short length. Check the pitch over a full inch, and check the thread angle (55° for BSP, 60° for JIC). 1 NPT is similar in size and pitch, but tapers. Comparisons in detail: JIC vs BSP, JIC vs NPT, JIC vs ORFS, JIC vs SAE 45°.
Torque and flats for -16 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 flat (from Tameson; Parker's cell was not legible); reference 118 ft-lb (160 N·m) | FFWR is the recommended method |
| Tameson JIC assembly guide, flared tube nut / swivel nut | 1-1/2 flats / 1 flat | Tube nuts take more rotation than swivels |
| Hose and Fittings assembly chart, tube / swivel | 1 flat / 1 flat; 115–125 ft-lb | Fewer tube flats than Tameson |
| SAE J514 range (as published by distributors) | 108–113 ft-lb (146–153 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.
-16 JIC next to its neighbouring sizes
There is no -18 JIC in common use, so the next size up is -20 (1-5/8-12). All three sizes in this table have 12 TPI, so separate them by diameter: about 30.2 mm for -14, 33.3 mm for -16 and 41.3 mm for -20.
| Dash | Tube OD (in) | Thread | Male OD (mm) | Female ID (mm, approx.) |
|---|---|---|---|---|
| -14 | 7/8 | 1-3/16-12 | 30.16 | 27.9 |
| -16 | 1 | 1-5/16-12 | 33.34 | 31.2 |
| -20 | 1-1/4 | 1-5/8-12 | 41.28 | 39.1 |
Hose, tube and adapters
On most hydraulic hose, a -16 dash number means a 1 in inside diameter. SAE 100R5 hose follows tube sizing instead, so a -16 R5 hose has a 7/8 in bore (see JIC hose end sizes). To connect a -16 JIC line to a different port, use an adapter with a male -16 JIC end and the matching port end, for example -16 ORB or 1 NPT. Published working pressures fall as size increases; see the JIC pressure rating page. 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, -12 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 -16 JIC fitting?
1-5/16-12 UN: 1-5/16 in (33.34 mm) major diameter with 12 threads per inch.
What tube size is -16 JIC?
1 in OD tube (25.4 mm). The dash number is the tube OD in sixteenths of an inch: 16/16 = 1 in.
Is -16 JIC the same as 1 inch JIC?
Yes. "1 in JIC" refers to the tube size. The thread is 1-5/16-12.
Will a -16 JIC fit a G1 BSP port?
No. The diameters are almost the same, but BSP has 11 threads per inch and a 55° thread form, and it does not seal on a 37° cone. Use a proper adapter.
How much torque does a -16 JIC need?
Tameson gives 1 flat from wrench resistance for a steel swivel, and Parker's reference torque is 118 ft-lb (160 N·m). Published SAE J514 ranges list 108–113 ft-lb. Follow your fitting maker's instructions.