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  1. #1
    Join Date
    Jan 2011
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    2

    Question Valve Stem Thread Pitch

    Adjusting the water temperature in my shower is very touchy. If I move cold water faucet handle one or two degrees rotation left or right, the temperature change swings from hot to cold in a manner difficult to control.

    Is it possible to find valve stems with a finer pitch that will allow a more gradual adjustment of the flow?

  2. #2
    Join Date
    May 2008
    Location
    Pacific Northwet
    Posts
    1,418

    Default Re: Valve Stem Thread Pitch

    Have you checked to see if the washer is worn or loose? Sometimes replacing or tightening the washer (if it's a "compression stop" type faucet) can fix the issue. Check both the hot and cold, as well as the mixing valve that switches between tub spout and shower head.

    You're not going to be able to change the thread pitch unless the inside threads are in a cartridge than can be removed -- the pitch must match in both the outside threads on the stem and the inside threads on the valve body. And then you'll probably have to have something custom machined, which will probably be more expensive than just replacing the whole works.
    The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

  3. #3
    Join Date
    Aug 2007
    Posts
    6,616

    Default Re: Valve Stem Thread Pitch

    Yeah, you're not going to be able to change anything about the valve itself, but you can rebuild it so that it performs better. My guess is that the screw that holds the seat washer in place is loose and moving around as you're trying to adjust the temp.

    Turn off the water to the house, disassemble the valves, replace the seat washers, reassemble, turn the water back on and check your work.

    Before starting, go to the hardware store and pick up a package of seat washers so you're ready to do the job from start to finish, having the water off for the shortest amount of time possible. Your family will thank you for that.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  4. #4
    Join Date
    Jan 2011
    Posts
    2

    Default Re: Valve Stem Thread Pitch

    Quote Originally Posted by Fencepost View Post
    Have you checked to see if the washer is worn or loose? Sometimes replacing or tightening the washer (if it's a "compression stop" type faucet) can fix the issue. Check both the hot and cold, as well as the mixing valve that switches between tub spout and shower head.

    You're not going to be able to change the thread pitch unless the inside threads are in a cartridge than can be removed -- the pitch must match in both the outside threads on the stem and the inside threads on the valve body. And then you'll probably have to have something custom machined, which will probably be more expensive than just replacing the whole works.
    The first thing I did was to replace the washers - both hot and cold. I know that they not are not loose because I know the symptoms of that condition. What I am asking about is: can I replace the whole valve stem assembly in which the threads - inside and out are finer that the existing ones. From the answers I have been getting, I assume there is only one standard thread pitch.

    Would changing from a flat washer to a conical washer help to allow a more gradual flow adjustment?

  5. #5
    Join Date
    Dec 2009
    Posts
    40

    Default Re: Valve Stem Thread Pitch

    something is wrong with your cold stem or cold water supply because nobody makes a valve that sensitive.if you dont have a stem problem then you might have a cold water pressure problem.

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