Fittings Not Fitting

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Knight, Dec 4, 2019.

  1. Knight

    Knight New Member

    Joined:
    Dec 4, 2019
    Location:
    Florida
    I have a Shako valve that supposedly has 1/4" NPT ports (purchased from overseas... I'm in the US). I went to Home Depot and purchased a 1/4" nylon barb to go in one end of the valve and a 1/4" NPT brass hex nipple to go in the other end. The nylon barb will not even start going into the port and the hex nipple (which is tapered) goes in only about two threads and then stops. I have re-checked the size specifications of the barb and hex nipple, which both clearly state 1/4".

    Is this normal for these fittings to be so tight and do I just have to wrench them in with more force? I don't want to damage the valve. Any suggestions? Thank You.

    upload_2019-12-4_17-47-9.png
     
  2. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    Go back to your hardware store and see if they have a thread guage. Its probably metric threads.

    Google produces a USA and a UK result too.. british threads!
     
    Last edited: Dec 4, 2019
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  4. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Maybe you did cross-thread the nylon piece.

    You could also compare the threads on the two pieces you bought. Are they the same pitch?

    The thread gauge is the right tool to check the block, but I kinda thought the photo made the threads on the nylon piece look to be finer pitch that the brass piece.
     
    Last edited: Dec 4, 2019
  5. Terry

    Terry Administrator Staff Member

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    Aug 17, 2004
    Occupation:
    Plumber
    Location:
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    I'm thinking they are metric too. They should thread in more than that.
     
  6. Knight

    Knight New Member

    Joined:
    Dec 4, 2019
    Location:
    Florida
    Thank you for your input. I had that thought as well (that one or the other was metric) I'm going back to the store tomorrow.
     
  7. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Take your Shako valve with you.
     
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  8. Knight

    Knight New Member

    Joined:
    Dec 4, 2019
    Location:
    Florida
    I never went past that point in the picture with the nylon barb. I do have one barb that fits well/easily into the valve. I do not know the specs on this barb. The valve is supposedly 1/4" NPT, however the hex nipple, which is also supposedly 1/4" NPT does not fit. Here is a picture of the threads and their corresponding fit into the valve.

    upload_2019-12-4_21-57-3.png
     
  9. Knight

    Knight New Member

    Joined:
    Dec 4, 2019
    Location:
    Florida
    Thank you for your response... confirming my thought that they should screw in farther than they are. Something is really 'off' here and I can't quite figure it out yet.
     
  10. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    https://en.wikipedia.org/wiki/National_pipe_thread says to expectabout 4 turns for Hand-tight engagement.

    Dies and taps can fix up threads that are too tight. I suspect out of spec NPT rather than metric, but it certainly could be a metric problem.
     
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