This connection is widely used in hydraulic systems. When the straight threads are engaged, the 37° male seat seals on the37° female flare seat.
A 37° fitting body will accept both inch and metric tube by changing the sleeve. The 37° adapter body are available in a variety of port end configurations.
Pressure Ratings
| SAE Dash Size | Nominal Tube OD (inch) | Thread Size | 37° Flared Tube Ends (psi) | 37° Female Swivels (psi) | SAE BOSS Studs (psi) | SAE Boss Adjustable Studs (psi) |
| -02 | 1/8 | 5/16 24 UNF | 5,000 | 5,000 | 5,000 | 5,000 |
| -03 | 3/16 | 3/8 24 UNF | 5,000 | 5,000 | 5,000 | 5,000 |
| -04 | 1/4 | 7/16 20 UNF | 5,000 | 4,500 | 5,000 | 4,500 |
| -05 | 5/16 | 1/2 20 UNF | 5,000 | 4,000 | 5,000 | 4,000 |
| -06 | 3/8 | 9/16 18 UNF | 5,000 | 4,000 | 5,000 | 4,000 |
| -08 | 1/2 | 3/4 16 UNF | 4,500 | 4,000 | 4,500 | 4,000 |
| -10 | 5/8 | 7/8 14 UNF | 3,500 | 3,000 | 3,500 | 3,000 |
| -12 | 3/4 | 1-1/16 12 UN | 3,500 | 3,000 | 3,500 | 3,000 |
| -14 | 7/8 | 1-3/16 12 UN | 3,000 | 2,500 | 3,000 | 2,500 |
| -16 | 1 | 1-5/16 12 UN | 3,000 | 2,500 | 3,000 | 2,500 |
| -20 | 1-1/4 | 1-5/8 12 UN | 2,500 | 2,000 | 2,500 | 2,000 |
| -24 | 1-1/2 | 1-7/8 12 UN | 2,000 | 1,500 | 2,000 | 1,500 |
| -32 | 2 | 2-1/2 12 UN | 1,500 | 1,125 | 1,500 | 1,125 |
| SAE Dash Size | Nominal Pipe OD (inch) | Thread Size NPTF & NPSM | Fittings w/ NPTF Pipe Threads (psi) | Fittings w/ NPSM Female Swivel (psi) |
| -02 | 1/8 | 1/8 27 | 5,000 | 5,000 |
| -04 | 1/4 | 1/4 18 | 4,000 | 5,000 |
| -06 | 3/8 | 3/8 18 | 3,000 | 4,000 |
| -08 | 1/2 | 1/2 14 | 3,000 | 3,500 |
| -12 | 3/4 | 3/4 14 | 2,500 | 2,250 |
| -16 | 1 | 1 11-1/2 | 2,000 | 2,000 |
| -20 | 1-1/4 | 1-1/4 11-1/2 | 1,150 | 1,625 |
| -24 | 1-1/2 | 1-1/2 11-1/2 | 1,000 | 1,250 |
| -32 | 2 | 2 11-1/2 | 1,000 | 1,125 |
NPTF – Dryseal American Standard Taper Pipe Thread
NPSM – American Standard Straight Pipe Thread for Mechanical Joints
JIC Fitting Tube Assembly
For leak-free performance, the JIC flared hydraulic fittings requires these steps:
1: Cutting, deburring, and cleaning of the tube
2: Flaring
3. Flare inspection
4: Installation
Flaring
Several flaring methods, ranging from simple hand flaring to hydraulic/electric power flaring, are available. Power flaring is quickerand produces more accurate and consistent flares compared to hand flaring. Therefore, it is a preferred method of flaring. Handflaring should be limited to places where power flaring tools are not readily available. Prior to flaring, determine the tube length allowance using Table 1. This tube length allowance should be added to the cut tube lengthto allow for the “loss” of tube caused by flaring.
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Flare Inspection
Inspect flare for dimensions and surface quality. The sleeve can be used for a quick check of the flare dimensions as shown in Figure 2.
Figure 2 – Comparing flare O.D. with sleeve seat and O.D.
Underflaring (see Figure 3) reduces contact area causing excessive nose collapse and leakage; or, in extreme cases, tube pull outunder pressure.
Overflaring (see Figure 3) causes tube nut thread interference, either preventing assembly altogether, or giving a false sense of jointtightness resulting in leakage.
Figure 3 – Underflaring & Overflaring
The flare must be reasonably square and concentric with the tube O.D.; and it’s surface must be smooth, free of rust, scratches, splits, draw marks,weld beads, burrs, embedded chips, or dirt. If the flare does not meet these requirements, cut it off, take corrective action, and reflare.
Installation
Improper flaring or installation causes over 1/2 of the leakage problems with flared fittings. Therefore, proper installation is critical fora trouble free operation.
Figure 4 – Improper bend and short tube
Torque Specifications
Align the tube on the flare (nose) of the fitting body and tighten the nut using one of the two methods below.
- Flats from Wrench Resistance (FFWR) or “Flats” method
- Torque method
Note: Do not force an improperly bent tube into alignment (Figure 4) or draw in too short a tube using the nut. It puts undesirablestrain on the joint eventually leading to leakage.
Flats Method
Tighten the nut lightly with a wrench (approximately 30 in.lb.), clamping the tube flare between the fitting nose and the sleeve. This isconsidered the Wrench Resistance (WR) position. Starting from this position, tighten the nut further by the number of flats from the Torque Chart. A flat is referred to as one side of the hexagonal tube nut and equates to 1/6 of a turn. This Flats Method is more forgiving of the two. It circumvents the effects of differences in plating, lubrication, surface finishes, etc., that greatlyinfluence the torque required to achieve proper joint tightness or clamping load. Therefore, it is recommended to use this method whereverpossible, and especially where the plating combination of components is not known, and during maintenance and repair where components may beoily.
| Condition | Recommended Tightening Method |
|---|---|
| Plating of all components is the same | Either method will work |
| Plating is mixed | Use FFWR Method |
| Plating of nut and sleeve/hose end is unknown | |
| Parts are oily | |
| Stainless or brass components |
It is recommended that wherever possible, the step of marking the nut position relative to the body should be done.This step serves as aquick quality assurance check for joint tightening. To do this, at the initial wrench resistance position, make a longitudinal mark on one ofthe flats of the nut and continue it on to the body hex with a permanent type ink marker as shown in Figure 5. Then, at the properly tightenedposition, mark the body hex opposite the previous mark on the nut hex.
| Figure 5 – Make a reference mark on nut and tube body | These marks serve 2 important functions:
|
The flats method is slower than the torque method, but it has the 2 advantages described earlier, namely, circumvention of platingdifferences and a quick visual check for proper joint tightening.
Torque Method
With proper tube flare alignment with the nose of the fitting, tighten the nut to appropriate torque value. This method is fast & accurate whenpreset torque wrenches are used. Consistent component selection is recommended so that the effects of dissimilar plating is not an adversefactor in joint integrity. This makes it desirable for high production assembly lines. However, a joint assembled using the torque method canonly be checked for proper tightening by torquing it again.
Note: This method should not be used if the type of plating on the fitting and mating parts (sleeve & nut/hose swivel) is not known.The torque method should not be used for lubricated or oily parts as improper clamping forces may result. Over-tightening and fitting damagemay occur as a result.
| Thread Size | Assembly Torque (in-lb) | Assembly Torque (ft-lb) | Tube Connection FFWR | Swivel Nut or Hose FFWR |
|---|---|---|---|---|
| 2 | 35 – 45 | 2 – 4 | N/A | N/A |
| 3 | 65 – 75 | 5 – 7 | N/A | N/A |
| 4 | 130 – 150 | 11 – 13 | 2 | 2 |
| 5 | 165 – 195 | 14 – 16 | 2 | 2 |
| 6 | 235 – 265 | 20 – 22 | 1.5 | 1.25 |
| 8 | 525 – 575 | 43 – 47 | 1.5 | 1 |
| 10 | 650 – 750 | 55 – 65 | 1.5 | 1 |
| 12 | 950 – 1050 | 80 – 90 | 1.25 | 1 |
| 14 | 1200 – 1300 | 100 – 110 | 1 | 1 |
| 16 | 1400 – 1500 | 115 – 125 | 1 | 1 |
| 20 | 1900 – 2100 | 160 – 180 | 1 | 1 |
| 24 | 2250 – 2550 | 185 – 215 | 1 | 1 |
| 32 | 3000 – 3400 | 250 – 290 | 1 | 1 |
