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    Re: A-10 Sextant Maintenance Manual
    From: Jean-Philippe Planas
    Date: 2007 Dec 15, 09:55 -0800
    Hi Robert,

    In fact I had to make the neoprene O-ring gaskets myself. It is possible to buy "kits" in which you find neoprene strings of different diameters. You chose the diameter  that fits, cut the correct amout of length and glue both ends together with a neoprene compatible glue.
    Regards
    JPP

    Robert Eno <enoid{at}northwestel.net> wrote:
    Ditto my last note.
     
    I'm losing it.  Sorry Jean-Philippe.
     
    Robert
    ----- Original Message -----
    From: Robert Eno
    Sent: Saturday, December 15, 2007 11:46 AM
    Subject: [NavList 4325] Re: A-10 Sextant Maintenance Manual

    Nicolas or anyone else:
     
    Do you know of a supplier of said gaskets and/or neoprene rings?  I have a few A-10 units here which I promised to repair for a guy and cannot get the damn fluid to stay in the chamber.
     
    From my remote location, it is difficult to identify and locate suppliers of such obscure materials.
     
    Robert
    ----- Original Message -----
    Sent: Saturday, December 15, 2007 5:43 AM
    Subject: [NavList 4323] Re: A-10 Sextant Maintenance Manual

    If you save the lead gasket at §4 and replace it at §9 (recommended by the repair manual) you might not have to change it for a neprene O ring. Also if this lead gasket is firmly stuck to the lens, do not attempt to unstick it, leave it in place. At §9 replace the lens carefully so that the lead gasket sits correctly in its channel (sometimes the lead gasket seems to be stuck out of center under the lens.
    But if the lead gasket is damaged either by age or by the dismounting procedure, it will not be reusable and you will have to use a neoprene O-ring.
    JPP

    Camelot <Camelot816---.com> wrote:

    Thank you for the very complete information, I am working on the
    bubble problem with a Navy machinist friend who has worked on small
    instruments.We should be able to handle it succesfully. Well probably
    get together in a couple of weeks. Both of us are socents on the
    Battleship New Jersey now housed in Camden, NJ

    Thanks again, and excuse the delay in getting bacvk to you. I'll let
    you know how it goes.





    On Dec 11, 2:33�pm, jean-philippe planas
    wrote:
    > As I am not sure this answer went through the net and reached Arthur, I repost it.
    > If it did go through the net, please disregard it.
    >
    > The bubble assembly has to be refilled with xylene which is some kind of a paint solvent.
    > You have to separate the bubble assembly from the main sextant body.
    > 1- Unscrew the 2 small screws that maintain the lighting arrangement below the assembly.
    > 2-Unscrew the 4 main long screws to separate the bubble assembly from the optical system.
    > 3-Unscrew the bottom lens of the bubble assembly
    > 3-1 with a wristwatch caseback wrench, �unscrew the lens retainer ring.
    > 3-2 carefully remove with a blade the metal and paper compression gaskets
    > 3-3 unstick the lens with a thin blade or a suction cup
    > 4 Remove the thin lead inner gasket and be prepared to replace it by neoprene O ring that fits in the lead gasket channel. The O ring is about 1.5mm thick by 20mm diameter.
    > 5 Take out all remaining fluid by operating the �enlarger �knob back and forth
    > 6 Clean the lens and inner of the bubble assembly with fresh xylene and �Q-tips
    > made of natural �cotton
    > 7 Pour fresh xylene into the cavity (top it up) and work the enlarger knob back and forth to eliminate air from the reservoir. Repeat the operation until no more bubbles appear from the reservoir.
    > 8 Top up again the cavity with xylene
    > 9 Place neoprene O ring in place and lens
    > 10 Replace paper and metal compression gaskets above the lens
    > 11 Replace the bottom lens retainer ring and screw it by hand only
    > 12 With your fingers of one hand applying controlled pressure on the top and bottom lenses, with the other hand carefully work the enlarge-reduce knob until a small bubble appear
    > 13 Tighten the bottom retainer ring with the watch caseback wrench
    >
    > Check the bubble after one or two days. If it grows you will have to repeat the process. Sometimes it is necessary to repeat the process numerous times until you get a stable bubble of the right size (about 1.5 or 2mm diameter)
    >
    > The enarge reduce pump system will most �likely not be working anymore as these bubble assemblies used to be filled under a vacum to correctly operate as specified.
    >
    > Hope this helps
    >
    > JPP
    >
    > glap...---.net wrote:
    > Gary writes:
    >
    > I will look at my A-10 manual tonight to see if it has this
    > information.
    >
    > gl
    >
    > On Dec 6, 11:56 am, Camelot �wrote:
    >
    > > I need assistance in loading or refilling the bubble on an A-10 WW II
    > > Air Force Sextant. If you can help, or direct me to help, please
    > > replThank you.
    >
    > > Arthur Hill
    >
    > ---------------------------------
    > Looking for last minute shopping deals? �Find them fast with Yahoo! Search.

    Never miss a thing. Make Yahoo your homepage.



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