A -3 Male Flare Union is a type of fitting used to connect two female Aircraft/Navy (AN) hose ends or fittings. The "-3" refers to the size, with each dash representing a specific fraction of an inch. The "male" designation means it has male threads on both ends, and the "flare" refers to the 37-degree sealing surface.Â
Key characteristics
-3 AN size:Â In the AN sizing system, the number represents the tubing's outer diameter in 1/16th of an inch. A "-3" is 3/16-inch. This sizing standard is common in high-performance automotive and motorsport applications, particularly for brakes.
Male threads on both ends:Â This union has external threads at both ends, designed to be screwed into two separate female-threaded fittings. This creates a secure and leak-proof connection.
37-degree flare:Â The sealing surface of the fitting has a 37-degree angle, which makes a metal-to-metal seal with the flared end of a tube or the internal cone of a female fitting. This creates a high-pressure, durable connection that does not require sealants or washers.
