Proper Assembly Steps for 37° Flare Fittings Using the Flats Method
- Jan 18, 2019 -
Properly assembling your fitting connections help to ensure that your systems install and stay leak-free. This is why we have started a series of assembly posts/videos featuring the proper assembly of the most popular tube and port ends. Today we are talking about the proper assembly steps for 37° flare fittings, which are also known as JIC fittings. Improper flaring or installation causes over half of the leakage with flared fittings. Thus, proper installation is critical for trouble-free operation.
For the 37° flare fitting, the flats method of installation is recommended because it is more forgiving than the torque method. It circumvents the effects of friction due to the differences in plating surfaces, finishes, and lubrication that can greatly influence the torque required to achieve proper joint tightness or clamping load.
Watch the video to learn the proper process for assembly of 37° flare fittings, or follow the steps outlined below.
Proper 37° flare fittings assembly and installation steps:
Step 1: Check your flared tube, if applicable.
If connecting to a flared tube, start by verifying that the tube end is properly flared. The flare should be reasonably square and concentric with the other diameter of the tube. Ensure that it is free from rust, scratches, splits, embedded chips, and dirt, all of which can compromise the connection.
Step 2: Align the flare ends and tighten.
Next, align the flared tube or hose end with the nose of the fitting. Lightly tighten the nut until you feel wrench resistance, approximately 30-inch pounds will be needed.
Step 3: Mark the nut.
It's good practice to mark the nut position relative to the body. Using a permanent marker, make a mark on one of the flats of the nut and continue the mark to the body of the fitting.
Step 4: Tighten using recommended flats.
Now tighten the nut further using the number of flats recommended. A flat is equivalent to one side of the hexagonal nut, or one-sixth of a turn.
Step 5: Make a second mark on the fitting.
Once properly tightened, use a permanent marker to place a second mark on the fitting adjacent to the previously marked line on the nut. This second mark serves as a check that the connection has been tightened during final inspection and allows for an easy check to see if the nut has come loose and backed off during operation. It also provides a reference for subsequent remakes.
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