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Old 72 question

Discussion in 'Tanks, Valves and Bands' started by MaxE, Jul 25, 2019.

  1. Bob DBF

    Bob DBF Solo Diver

    # of Dives: I just don't log dives
    Location: NorCal
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    I hope he checks, if his luck is like mine.

    I have a 1/2 NPSM valve in a bin somewhere, but I've not seen a NGT tank. I don't think there were a lot made, as 3/4 NPSM took over as the standard at that time.


    Bob
     
  2. Bob DBF

    Bob DBF Solo Diver

    # of Dives: I just don't log dives
    Location: NorCal
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    Mate it up against a peice of 1/2 threaded pipe.

    Edit
    If you had to fight to get the valve off, its probably a tapered thread.


    Bob
     
  3. MaxE

    MaxE DIR Practitioner

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  4. Bob DBF

    Bob DBF Solo Diver

    # of Dives: I just don't log dives
    Location: NorCal
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    Looks like NPSM from here, but I'd still lay it up against a threaded 1/2 inch pipe. It would be an expensive mistake to guess wrong.


    Bob
     
  5. MaxE

    MaxE DIR Practitioner

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    NGT? The valves for sale are NPT, I’m taking that these are different, if it were NGT, can those valves be purchased anywhere? The fact that NPT valves are still being made leads me to believe these were the more common option back in the day?
     
  6. runsongas

    runsongas Great White

    # of Dives: 500 - 999
    Location: California - Bay Area
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    National Gas Taper vs. NPT

    The short answer is NGT and NPT are interchangeable, NGT has more threading for a given nominal size
     
    Bob DBF likes this.
  7. rhwestfall

    rhwestfall Solo Diver

    # of Dives: 200 - 499
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    vernier caliper measurements will tell you if you have tapered or straight...
     
  8. abnfrog

    abnfrog Tech Instructor

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    its straight............ tapered is obvious
     
    AfterDark and rhwestfall like this.
  9. Sam Miller III

    Sam Miller III Scuba Legend Scuba Legend

    # of Dives: 5,000 - ∞
    Location: CALIFORNIA: Where recreational diving began!
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    Sportsways Catalog
    7701 East Compton Blvd< Paramount, California

    Part # 1104k $7.95 1/2 inch Standard Pipe Thread
    O ring sealed

    SDM
     
    captain and Scuba Lawyer like this.
  10. herman

    herman Divemaster

    # of Dives: 500 - 999
    Location: Raleigh,North Carolina
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    Healthways (maybe others??) sold some tanks with 1/2 straight threads that used an oring. I have a couple of those tanks. The valves are a little hard to find but show up from time to time. ....There are a few old tanks that had that indented bottom, seems like mine also had the 1/2 HW valve.
    The conical groove or flare at the top of some of the tanks is the oring seat, standard modern valves will work with it. Its common for the old oring to look like some kind of tapered gasket, it started life round like other orings but over the years took a set to look like the groove. Replace it with a new oring. Most modern tanks just use an enlarged straight area instead of the tapered area.
     

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