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SP G250 jam nut

Discussion in 'Do It Yourself - DIY' started by couv, Apr 4, 2018.

  1. buddhasummer

    buddhasummer Bat sh.t crazy ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Nanny State
    11,933
    4,510
  2. 1967Goat

    1967Goat Contributor

    # of Dives: 50 - 99
    Location: Conifer, CO
    124
    162
    Put me down for 8. I've been picking up G250's on Craigslist over the past year or so.
     
  3. Open Ocean Diver

    Open Ocean Diver ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 50 - 99
    Location: Toronto, Lauderdale-by-the-Sea
    1,135
    746
    Once I receive the Halcyon Jam Nut sample, I’ll have one made and tested comparing to the sample.
     
  4. Open Ocean Diver

    Open Ocean Diver ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 50 - 99
    Location: Toronto, Lauderdale-by-the-Sea
    1,135
    746
    Round and flared like this?

    Halcyon halo nut:

    upload_2021-2-17_7-42-46.jpeg
     
  5. buddhasummer

    buddhasummer Bat sh.t crazy ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Nanny State
    11,933
    4,510
    I think the same design would be great. A normal "nut" wouldn't be in full contact with case.
     
  6. rhwestfall

    rhwestfall Woof! ScubaBoard Sponsor

    # of Dives: 200 - 499
    Location: "La Grande Ile"
    16,585
    19,698
    I'm wondering if a ss washer does the trick? Yeah, Simon's OCD can't handle that... A proper shaped one would be favorable. Watching this...
     
    Modi likes this.
  7. buddhasummer

    buddhasummer Bat sh.t crazy ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Nanny State
    11,933
    4,510
    Bob, noooooooooo
     
    rhwestfall and tridacna like this.
  8. buddhasummer

    buddhasummer Bat sh.t crazy ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Nanny State
    11,933
    4,510
    I'll post side by side photo tomorrow with specs.
     
    Modi and rhwestfall like this.
  9. Geo7

    Geo7 Contributor

    # of Dives: 2,500 - 4,999
    Location: Los Angeles
    213
    120
    Yup, that's the one I'll be sending your way tomorrow...
     
    couv and buddhasummer like this.
  10. 1967Goat

    1967Goat Contributor

    # of Dives: 50 - 99
    Location: Conifer, CO
    124
    162
    The nut in the picture from open water diver is the Halcyon nut. That nut will not work on a G250. The flared shoulder is too big. In my possession I have 4 G250V's, 3 G250's and 6 of the Halcyon nuts for the G250V's.

    The OD of the flared shoulder on the Halcyon nut is .895"
    The wrench flats on the Halcyon nuts is .667".
    The Halcyon nut is .500" thick.
    The points on the wrench flats are .743" (widest points).
    The OD of the splined nut for the G250 is .743" and is .75" thick.
    A typical nut with the 9/16 thread is .870 on the wrench flats, .992 at the points.
    The Halcyon nuts will not screw down on to the G250 because the .895 flare is took large, it hits the exhaust tee.
    If you flip the nut over, the nut will clear and tighten down correctly.

    IMO, the nut needs to have wrench flats of .667", points of .743" and be .375" thick.

    I am not sure why the base of the nut needs to be round (flare) and not a typical hex shape.
     

    Attached Files:

    Pressurehead and couv like this.

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