Frankly only shops I have visited fail completely in providing an indication about what exactly they are selling when it comes to keg fittings.

I have read this answer to another question, which was asking less generally then this, also about the fittings for keg connectors.

My question is: What are the different standards related to those fittings, what, and more over how can I measure which fitting I have?

Bonus: Is it only my impression that online shops do extremely poorly with regards to providing any, or if so accurate description about the fittings.

Example: I have two fittings enter image description here I can tell that the outer diameter of the red fitting is about 12.60mm / 0.496inches and of the black one it is about 10.86 mm / 0.427 inches.

Part of an answer could also be which of those fittings sizes/descriptions like MFL, actually exists, or are merely customarily used, but are not actually a "thing".

1 Answer 1



SAE J512/4 - 12.7mm is 1/2-20 and 9.5mm is 3/8-24 or 11.1mm is 7/16-20. (10.86mm is not one of the available sizes).


Note: For sizes 3/16 to 3/8 and 1/2 to 3/4 the flare type fittings depicted in Figures 1A to 3C are identical with the corresponding refrigeration tube fittings specified in SAE J513. Special size combination fittings 3/16 to 3/8 and 1/2 to 3/4 shall be as specified in SAE J513.

See also:


It appears that those are 37° MFLs (J514).

  • 1
    Hi Rob, this is quite some information you have put together. My question originated with the challenge that is the variety of threadings available and hence the needed terminology and ways to identify a threading. I will reread you answer and attempt to see if I can corroborate and identify that it is a J514. thanks already a lot and I will accept your answer gladly as soon as I found the time to reread it and check the part :). thank! Commented Apr 9, 2019 at 14:41

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