The flare angle of a JIC flare fitting is 37 degrees. Which option lists the flare angle correctly?

The flare angle of a JIC flare fitting is 37 degrees. Which option lists the flare angle correctly?

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

Answer: (D)

JIC flare fittings are designed around a 37-degree flare because this specific taper creates a reliable metal-to-metal seal with the matching seating surface. The 37° cone seats tightly as the nut is tightened, distributing the load evenly and resisting high pressure and vibration typical of hydraulic systems. Using any other angle would prevent proper seating and likely cause leaks or failure. Other flare families do use different angles (for example, some brake-line or aerospace fittings use 45°), but for JIC the standard and correct flare angle is 37 degrees.

JIC flare fittings are designed around a 37-degree flare because this specific taper creates a reliable metal-to-metal seal with the matching seating surface. The 37° cone seats tightly as the nut is tightened, distributing the load evenly and resisting high pressure and vibration typical of hydraulic systems. Using any other angle would prevent proper seating and likely cause leaks or failure. Other flare families do use different angles (for example, some brake-line or aerospace fittings use 45°), but for JIC the standard and correct flare angle is 37 degrees.