Size charts
JIC Hydraulic Fitting Thread Size Chart (-2 to -24)
In short
This JIC thread size chart matches each dash size to its thread. JIC (SAE J514, 37° flare) dash sizes are the tube OD in sixteenths of an inch: -4 = 7/16-20, -6 = 9/16-18, -8 = 3/4-16, -10 = 7/8-14, -12 = 1-1/16-12, -16 = 1-5/16-12. Measure the male thread OD with calipers, check the pitch, and find the matching row.
JIC thread size chart
| Dash size | Tube OD (in) | Thread (in-TPI) | Male thread OD, measured (in) | Female thread ID, measured (in) |
|---|---|---|---|---|
| -2 | 1/8 | 5/16-24 | 0.31 | 0.27 |
| -3 | 3/16 | 3/8-24 | 0.38 | 0.34 |
| -4 | 1/4 | 7/16-20 | 0.44 | 0.39 |
| -5 | 5/16 | 1/2-20 | 0.50 | 0.45 |
| -6 | 3/8 | 9/16-18 | 0.56 | 0.51 |
| -8 | 1/2 | 3/4-16 | 0.75 | 0.69 |
| -10 | 5/8 | 7/8-14 | 0.88 | 0.81 |
| -12 | 3/4 | 1-1/16-12 | 1.06 | 0.98 |
| -14 | 7/8 | 1-3/16-12 | 1.19 | 1.10 |
| -16 | 1 | 1-5/16-12 | 1.31 | 1.23 |
| -20 | 1-1/4 | 1-5/8-12 | 1.63 | 1.54 |
| -24 | 1-1/2 | 1-7/8-12 | 1.88 | 1.79 |
Measured values are approximate. Real threads read a little under the nominal size on a male fitting and a little over the root diameter on a female one. We left out -32: we found only one source for it and want two before we publish a size.
How to identify a JIC fitting
- Relieve the pressure first. Lower the implement, shut the machine off, and work the controls to bleed off pressure before you loosen anything. Never feel for a leak with your hand; use cardboard.
- Measure the thread. Calipers across the male thread OD, or across the female thread ID.
- Check the pitch with a thread gauge: 24, 20, 18, 16, 14 or 12 TPI for JIC.
- Check the seat. JIC has a 37° flare cone. A seat-angle gauge tells 37° (JIC) from 45° (SAE flare).
- Match the row. For example, an OD of about 0.56 in with 18 TPI and a 37° cone is a -6 JIC.
Common mistakes
- Mixing JIC (37°) and SAE 45° flare. Many sizes share the same thread, so they screw together, but the cones don't seal.
- Reading the dash size as the thread size. A -8 fitting has a 3/4 in thread, not a 1/2 in thread; the 1/2 in is the tube OD.
- Calling a metric fitting JIC. Metric hydraulic fittings use millimeter threads. If the gauge doesn't match a JIC pitch exactly, it may be metric.
- Over-tightening to stop a leak. A leaking JIC joint can mean a damaged flare, a mismatched seat or dirt on the cone, and extra force won't fix those. Tighten to the fitting maker's spec; going past it can damage the flare.
Not sure what fitting you have? Snap it
Snap the fitting next to a ruler and Mechy helps you narrow down the thread type and dash size. Confirm the thread with a gauge and the seat angle before you order. Replacing a hose? Get the hydraulic hose repair steps.
Questions
What thread is a -6 JIC fitting?
9/16-18. A -6 JIC fits 3/8 in tube (6/16 in), and the male thread measures about 0.56 in across.
What thread is a -8 JIC fitting?
3/4-16, for 1/2 in tube. The male thread measures about 0.75 in across.
What does the dash size mean on a JIC fitting?
The tube OD in sixteenths of an inch. -4 is 4/16 = 1/4 in tube, -8 is 8/16 = 1/2 in, -16 is 16/16 = 1 in.
Is JIC the same as SAE 45° flare?
No. Many sizes share the same thread, but JIC seals on a 37° flare and SAE flare on a 45° flare. Mixed together they leak.
How do I measure a JIC fitting?
Measure the thread OD (male) or ID (female) with calipers, check the pitch with a thread gauge, and confirm the 37° seat with a seat-angle gauge. Then match the reading to the chart.
Sources
Updated
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