Which angle is used for JIC hydraulic fittings flare?

• A. 30 degrees
• B. 45 degrees
• C. 60 degrees
• D. 37 degrees

Answer: (D)

Understanding the flare angle used by JIC fittings is essential for a proper seal. JIC fittings use a 37-degree flare, so the formed end of the tubing and the mating seat in the fitting meet at a 37-degree conical angle. When the nut tightens, the 37-degree flare is pressed against the matching 37-degree conical seat, creating a metal-to-metal seal that can withstand high hydraulic pressures. If the angle is different, the flare won’t align correctly with the seat, preventing a proper seal and likely causing leaks. The other angles listed do not match the JIC standard, which is why 37 degrees is the correct choice. For best results, use the correct flaring tool to produce a precise 37-degree flare and inspect the flare for any damage before assembly.