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  • Merchant Coupling?

    Now I am some what confused,
    the normal supplyer I use sells 95% of the pipe couplings are of the "Merchant Coupling" style. (his statements), and he has been supplying to governmental and independent plumbers in the area for 50 years.

    one day I was in an ACE hardware, store, and waling through the plumbing supplies, and I note this on the box with the "Merchant Couplings" it said ,"For non-plumbing applications". I checked there web site, and yes it restated there, under product details.
    http://www.acehardware.com/product/i...entPage=family
    or
    http://www.acehardware.com/product/i...entPage=family

    but I check other locations, and (example) Merrill which manufactures well supplies and hydrants, and Merchant Couplings for use in water lines and well drop pipe,

    most of the pipe I buy has the "Merchant Coupling" on one end,

    and I have seen no disclaimer on other sites,
    http://www.canvil.com/pages/catalogs/scf-p3.htm
    http://www.maassmidwest.com/catalog_...7_CplsNpls.pdf
    http://www.fastenal.com/catalog_pages/2004/1157.pdf
    and I looked up other as well, and could see no disclaimers,

    Any one have an understanding of why? ACE states that on there Merchant Coupling?
    or is there something more I should know about Merchant Couplings?
    Push sticks/blocks Save Fingers
    ~~~~~~~~~~~~~~~~~~~
    "The true measure of a man is how he treats someone who can do him absolutely no good."
    attributed to Samuel Johnson
    ~~~~~~~~~~~~~~~~~~~
    PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

  • #2
    Re: Merchant Coupling?

    good question bhd

    i was always under the impression that the so called coupling that came with the length of a 21' piece of pipe was there as a thread protector or merchant coupling. typically a merchant coupling is threaded all the way with a straight thread. we never used them as a pipe coupling, but rather as a hanger end stop.

    this is what i found on one of your links.

    Merchant couplings in NPS 1/8 through 2 are normally
    supplied straight tapped. NPS 2 1/2 and larger are
    taper tapped.

    Taper tapped standard merchant couplings in NPS 1/8
    through 2 are available upon request.

    the tapered ones are the ones that you need to use. the ones that come on the end of our lengths of pipe are non tapered.

    some brands of left and right couplings typically used for gas, are an example of a tapered merchant coupling.

    an electricians threaded coupling is an example of a non tapered and approved merchant coupling.

    the couplings that we purchase in the supply house are typically not merchant style couplings, for the exception of left and right couplings as explained earlier.

    hope your not more confused than before the question.

    rick.
    phoebe it is

    Comment


    • #3
      Re: Merchant Coupling?

      To add to what Rick posted, standard plumbing couplings are made from malleable iron where merchant couplings are made from steel tubing. In plumbing you generally only see merchant couplings used as thread protectors when shipping pipe.

      Merchant couplings are used more in areas where you need stronger fittings like in water wells. I have buckets or merchant couplings to go with my well piping up in Utah. My well piping is in 10' lengths and if I need to cut it shorter I cannot use tapered threads.

      It seems to take the punishment of a sledge hammer a lot better than a malleable iron coupling.

      Mark
      "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

      I never lost a cent on the jobs I didn't get!

      Comment


      • #4
        Re: Merchant Coupling?

        OK I under stand if it is straight threaded, that it will not tighten as tight, and thus will not seal, as efficiently,

        also, when I looked at some of the the other urls http://www.maassmidwest.com/catalog_...7_CplsNpls.pdf
        I noticed that some manufactures make a number of different styles of them (guessing meeting different requirements), my be they would not all be classified as merchant couplings.

        and a lot of my experience has been well drop pipe,

        OK,
        But as a protector, why is it only on one end? (or that has been my experience), I would think if it would be sent as a protector only, It would be half of a coupling in length, and put on both ends,
        as least that way you would have to "buy" more product.

        Thank you for your input, and responses.

        ~~~~~~~~~~~~~~~~~~~~

        Merchant couplings are used more in areas where you need stronger fittings like in water wells. I have buckets or merchant couplings to go with my well piping up in Utah. My well piping is in 10' lengths and if I need to cut it shorter I cannot use tapered threads.
        I under stand the idea of pipe being in 10' lengths, (ours is all 21', some of the old well pipe was 18') all our well drop pipe is tapered threads, on the pipe, yes the steel merchant couplings are on the drop pipe. (i think the couplings are tapered as well as the current pipe is 2", and I think even the 1 1/4" the couplings used tapered threads in the couplings.
        but I guess I am not understanding the statement,
        if I need to cut it shorter I cannot use tapered threads.
        do you thread the pipe with straight threads? And why cant you use tapered threads?

        All I know is ever day there is some thing I still need to learn,
        Last edited by BHD; 03-12-2007, 08:43 PM. Reason: more questions.
        Push sticks/blocks Save Fingers
        ~~~~~~~~~~~~~~~~~~~
        "The true measure of a man is how he treats someone who can do him absolutely no good."
        attributed to Samuel Johnson
        ~~~~~~~~~~~~~~~~~~~
        PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

        Comment


        • #5
          Re: Merchant Coupling?

          I think if you have tapered pipe and non tapered couplings you will only be utilizing the full bite of the widest threads.

          Comment


          • #6
            Re: Merchant Coupling?

            BHD,

            All black and gal pipe used in plumbing comes in 21' lengths with a plastic cap on one end and a merchant coupling on the other. I'm not sure why they do not use a plastic cap or a merchant coupling on both ends but they do not. A straight thread is used to connect pipes which don't necessarily need to be pressure tight. A tapered thread is used when the pipe must be pressure tight.

            Amongst other things I am the President of a Water Company in a rural area of Utah. All of my water is set up as a gravity system feed from an artesian source. The only mechanical pump in my system is a single battery operated chlorinating piston pump so I really do not need well piping. However, about 15-years ago I purchased a do-it-yourself well digging rig which digs a well which is one step up from a driven well. The piping comes in 10' lengths because of the limitations of the rig. Using both this rig or in a driven well you must use a merchant coupling as a standard plumbing coupling would snap in the middle of your project.

            Mark
            "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

            I never lost a cent on the jobs I didn't get!

            Comment


            • #7
              Re: Merchant Coupling?

              ToUtahNow that makes since on the DIY drilling rig, I understand the statement now,

              and yes I knew and understand the tapered on making pressure tight joints,

              and the straight on non pressure tight, (many times used in electrical rigid conduits),


              my wells are 280 feet deep no such thing as artesian wells around here,
              so the bottom pipes would have about 120 pounds of pressure.
              Push sticks/blocks Save Fingers
              ~~~~~~~~~~~~~~~~~~~
              "The true measure of a man is how he treats someone who can do him absolutely no good."
              attributed to Samuel Johnson
              ~~~~~~~~~~~~~~~~~~~
              PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

              Comment


              • #8
                Re: Merchant Coupling?

                Originally posted by ToUtahNow View Post
                To add to what Rick posted, standard plumbing couplings are made from malleable iron where merchant couplings are made from steel tubing. In plumbing you generally only see merchant couplings used as thread protectors when shipping pipe.

                Merchant couplings are used more in areas where you need stronger fittings like in water wells. I have buckets or merchant couplings to go with my well piping up in Utah. My well piping is in 10' lengths and if I need to cut it shorter I cannot use tapered threads.

                It seems to take the punishment of a sledge hammer a lot better than a malleable iron coupling.

                Mark
                I'm going to have a rare disagreement with Utah here. I'm wondering why you can't use a tapered thread on 10' lenghths. I also think that a "quality 150# tapered coupling is just as strong as a "thread protector". The tapered thread coupling obviously provides a better seal, what problems have you experienced?
                the dog

                Comment


                • #9
                  Re: Merchant Coupling?

                  Originally posted by plumbdog10 View Post
                  I'm going to have a rare disagreement with Utah here. I'm wondering why you can't use a tapered thread on 10' lenghths. I also think that a "quality 150# tapered coupling is just as strong as a "thread protector". The tapered thread coupling obviously provides a better seal, what problems have you experienced?
                  dog,

                  I may have confused you with my post. My 10' lengths of pipe have straight threads as supplied from the manufacturer because of the merchant couplings I am told to use with my well digging rig.

                  As for strength I am referring to the punishment a coupling takes in the drilling rig or with a driven well. A standard malleable iron coupling would not hold up as well as a steel coupling.

                  Mark
                  "Somewhere a Village is Missing Twelve Idiots!" - Casey Anthony

                  I never lost a cent on the jobs I didn't get!

                  Comment


                  • #10
                    Re: Merchant Coupling?

                    Originally posted by ToUtahNow View Post
                    dog,

                    I may have confused you with my post. My 10' lengths of pipe have straight threads as supplied from the manufacturer because of the merchant couplings I am told to use with my well digging rig.

                    As for strength I am referring to the punishment a coupling takes in the drilling rig or with a driven well. A standard malleable iron coupling would not hold up as well as a steel coupling.

                    Mark
                    Fair enough. I don't do well drilling, so I can't give an expert argument on this, so........I won't. I may have a water drilling question for you in the near future, so I'm glad to learn this is within your expertise.
                    the dog

                    Comment

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