-4 JIC Fitting Size and Dimensions
A -4 JIC fitting is for 1/4 in tube and has a 7/16-20 UNF thread. Here are its measurements, look-alikes and published tightening values.
Last updated October 30, 2026. Reference values; verify against manufacturer specifications.
The -4 JIC is the smallest size most people handle day to day. It is used on pilot and gauge lines, small cylinders, brake and clutch circuits on equipment, and lubrication lines. Because the fittings are small, a few tenths of a millimetre separate it from its neighbours, and its 7/16-20 thread is shared with two other fitting families. This page gives the full -4 dimensions, the fittings it is most often confused with, and the published tightening values.
-4 JIC at a glance
- Tube size: 1/4 in OD (6.35 mm). The dash number is the tube OD in sixteenths of an inch: 4/16 in = 1/4 in.
- Thread: 7/16-20 UNF: 0.4375 in major diameter, 20 threads per inch.
- Male OD: about 0.44 in (11.11 mm). Female ID: about 0.39 in (9.9 mm).
- Seat: 37° flare, metal-to-metal.
-4 JIC fitting dimensions
| Dimension | Inch | Metric |
|---|---|---|
| Tube OD | 1/4 in (0.250 in) | 6.35 mm |
| Thread | 7/16-20 UNF | pitch 1.270 mm |
| Threads per inch | 20 | 1.270 mm per thread |
| Male thread OD | 0.4375 in | 11.11 mm |
| Female thread ID (approx.) | 0.39 in | 9.9 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.
As with every JIC size, "-4" describes the tube, not the thread. A -4 JIC fitting has a 7/16 in thread, not a 1/4 in thread. Small sizes are also where worn or plated threads mislead most: a reading a few hundredths under 0.44 in is normal for a used male.
How to confirm a -4 JIC fitting
- Check the seat. A male -4 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 0.44 in (11.1 mm). A female should read about 0.39 in (9.9 mm) across the inner crests. See how to measure JIC fittings.
- Check the pitch. The 20 TPI leaf of an inch thread gauge should sit flush. The pitch is 1.27 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 -4 JIC
The 7/16-20 thread is used on -4 JIC, -4 SAE 45° flare and -4 ORB fittings. A male of any of these will thread into a female of the others, so the seat is the only reliable test. Several other fittings come close in diameter:
| Fitting | Thread | OD (in / mm) | TPI or pitch | How to tell |
|---|---|---|---|---|
| -4 SAE 45° flare (SAE J512) | 7/16-20 (same) | 0.44 / 11.11 | 20 TPI | 45° cone instead of 37° |
| -4 ORB (SAE J1926) | 7/16-20 (same) | 0.44 / 11.11 | 20 TPI | O-ring under the hex, no cone |
| -5 JIC | 1/2-20 | 0.50 / 12.70 | 20 TPI | Same pitch; about 1.6 mm larger |
| 1/8 NPT | 1/8-27 NPT | about 0.41 / 10.4 | 27 TPI | Tapered thread, finer pitch, no seat |
| G1/4 BSP | 1/4-19 BSP | about 0.52 / 13.2 | 19 TPI | 55° thread; larger and nearly the same pitch |
Look-alike threads from the Eaton and McGill thread identification guides, which agree on these sizes; metric threads are nominal.
The -4 SAE 45° fitting is the hardest to spot, because nothing about the thread is different. Check the cone with a seat gauge or compare it with a known part. The -5 JIC shares the 20 TPI pitch, so a thread gauge alone cannot separate -4 from -5; the caliper reading can (11.1 mm vs 12.7 mm). Comparisons in detail: JIC vs SAE 45°, JIC vs ORB, JIC vs NPT, JIC vs BSP.
Torque and flats for -4 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 | 2 flats; reference 13 ft-lb (18 N·m) | FFWR is the recommended method |
| Tameson JIC assembly guide, flared tube nut / swivel nut | 2-1/2 flats / 2 flats | Tube nuts take more rotation than swivels |
| Hose and Fittings assembly chart, tube / swivel | 2 flats / 2 flats; 11–13 ft-lb | Same swivel value as Parker |
| SAE J514 range (as published by distributors) | 11–12 ft-lb (15–16 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.
-4 JIC next to its neighbouring sizes
The -3 (3/8-24) and -5 (1/2-20) sit on either side of the -4. The -5 is the one that causes trouble: it has the same 20 TPI, and a worn -5 female can feel loose rather than wrong on a -4 male. The caliper reading settles it.
| Dash | Tube OD (in) | Thread | Male OD (mm) | Female ID (mm, approx.) |
|---|---|---|---|---|
| -3 | 3/16 | 3/8-24 | 9.53 | 8.6 |
| -4 | 1/4 | 7/16-20 | 11.11 | 9.9 |
| -5 | 5/16 | 1/2-20 | 12.70 | 11.4 |
Hose, tube and adapters
On most hydraulic hose, a -4 dash number means a 1/4 in inside diameter. SAE 100R5 hose is an exception: its dash follows the tube it replaces, so a -4 R5 hose has a 3/16 in bore (see JIC hose end sizes). To connect a -4 JIC line to a different port, use an adapter with a male -4 JIC end and the matching port end, for example -4 ORB or 1/8 NPT. The thread pitch of every size is on the JIC thread pitch chart, and the full range is on the JIC fitting size chart.
Other single-size pages: -6 JIC fitting size, -8 JIC fitting size, -10 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 -4 JIC fitting?
7/16-20 UNF: 7/16 in (11.11 mm) major diameter with 20 threads per inch.
What tube size is -4 JIC?
1/4 in OD tube (6.35 mm). The dash number is the tube OD in sixteenths of an inch: 4/16 = 1/4.
Is -4 JIC the same as 1/4 JIC?
Yes. "1/4 JIC" refers to the tube size. The thread is 7/16-20, not 1/4.
Is -4 JIC the same thread as -4 SAE 45° and -4 ORB?
Yes, all three use 7/16-20. They seal differently (37° cone, 45° cone and O-ring), so use an adapter instead of mixing them.
How much torque does a -4 JIC need?
Parker gives 2 flats from wrench resistance for a steel swivel, with a reference torque of 13 ft-lb (18 N·m). Published SAE J514 ranges list 11–12 ft-lb. Follow your fitting maker's instructions.