What Compression Fitting Do I Need?

I just bought a new fridge, but the delivery team won’t connect the water supply line to the existing water supply line. My problem is I have a 3/8" male threaded connection at BOTH the end of the copper supply and a 3/8" connection at the fridge intake. So, what do I need to make the connection? Googling around, I keep seeing a 1/4" compression fitting with two female ends to make the connection. So, is a 1/4" female threaded connector the correct mate for 3/8" male threaded connector? It seems logical, but is that correct?

Also, are brass fittings still acceptable for potable water service? Googling around, I saw something claiming it was until 2014. If so, can I find the desired fitting in copper?

Are you sure it’s a compression fitting ? From your description it may we’ll be that one is a compression and the other is NPT.

Post some pics so we can be certain.

If you are sure that you have male compression fittings on both sides -
Then a tune like this one will do the job :

No. Unsurprisingly, it takes a 3/8" female fitting to mate with a 3/8" male fitting.

What’s “NPT”? Can you post a picture of an NPT fitting, or such? In the meantime, (tomorrow), I have to figure out how to post a picture. I used to know, but I’ve forgotten and maybe it’s changed.

NPT is national pipe thread. Just go a google search on NPT fittings and you will get many pictures.

How did you decide it was compression fittings if you don’t know the difference between compression and NPT ?

If supply line and fridge both have male compression fittings the solution is easy. Make a female-female connector. Get 1 inch of 3/4 copper tubing. two 3/8 compression nuts and compression ferrols from your local hardware store. Assemble.

I suggest checking the return policies of the local hardware stores, since this is the kind of situation where one could buy five or six fittings that might work, just to narrow it down to the one that does and return the rest.

Actually it may easily turn out to be a combination of fittings–particularly if you use a local hardware store–which doesn’t have all kinds of specialized fittings.