Quote:
Originally Posted by ToddF
Wren,
Theoretical question: Given that the sealing surface of a push to connect fitting is the OD of the tube, well away from the end, why is the end of tube geometry critical to the sealing of the fitting? In other words, WHY does the end of the tube need to be perfectly square to seal properly?
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Good question! I've not seen that particular diagram before, but it does give you a bit of the wrong idea.
The seal isn't accomplished along a length of the tube, but instead at a very narrow band right near the end. If the tube isn't square, it may not sit entirely inside the band. The smaller and more compact the fitting, the narrower the sealing band is, and the more critical the square.
The other reason you want tubes to end square is the same reason that you cut stranded wires flush, instead of leaving whiskers. The gripper ring can be fouled by small slivers of tube that stick out, or they can impede airflow inside a fitting itself.