I am trying to install a Culligan FM-25 filter onto a faucet, and it does not seem to fit. I am able to screw on the filter, but it is not secure, and water bubbles/sprays out the top. It appears that the faucet head is too long (or has too many threads)? I know that my filter can accommodate 55/64"-27 M faucet spouts. If the filter at least partly screws onto the faucet, then isn't the faucet 55/64"-27 M as well? I can't find any examples of thread spacings other than 27 threads per inch for 55/64, so I'm assuming the faucet size is also 55/64"-27 M (but I could be wrong).
I have a picture of the faucet head as well as one of the water filter and aerator that I've removed from the faucet. As you can see, the aerator appears to be much deeper than the filter mount. Not only is there an unthreaded region above the threads, but I can count 4 visible levels of threading above the washer, whereas only 3 levels are visible on the mount of my filter.
If the faucet and filter are both 55/64", and yet the two are incompatible, I have no idea how to fix this, because surely there aren't any 55/64"-27 <-> 55/64"-27 adapters out there. I suppose I could try joining two adapters together, but it would probably make the end of the faucet too low.
- Threading of faucet is something like 24 per inch but same width, hence allowing me to screw on the filter, at least partially, but prevents a good seal.
- Width is slightly different (not sure if this is possible)
- Somehow faucet having too many threads prevents attachment of my filter
In the case of the first possibility, what thread size is the same width as 55/64"-27 M, but has <27 threads per inch?