Flair fittings seem to be consistently the most confusing fitting due to the close relation to pipe fittings. The outside diameter for both is very close. But after looking at the flare fittings a little closer the differences could not be greater.

There are a couple of different styles of flair. There is 45 degree flare fittings and inverted flare fittings.

 Let us take a look at the 45 degree fitting first. The flared tubing that would be used is intended to mate with the male flare on each end of the fitting and secured by a nut.

Not all flare fittings just have flare ends, some have compression and some may even have pipe.

The other style of flare fittings is the inverted flare. The process is exactly the same as the 45 degree flare. The reason or benefits for the inverted flare are shorter overall length, for limited space applications. Also, all of the seats and threads are recessed therefore protecting them.

Flare Thread Chart