[PSUBS-MAILIST] conical hatch seat troubles

Thu Dec 1 14:53:32 EST 2016

Hank - are you expecting the conical interface to perform as a metal to metal seal at depth? Or merely to carry the hull shell stresses? Do you know how much pressure is required to compress your o-ring sufficiently to reduce the extrusion gap to zero? Is this even possible? Or does the cone engage and prevent it?

Sean

On December 1, 2016 10:38:23 AM MST, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>Brian,I test for fit with the o-ring out.  Don't worry about yours,
>flat hatches will bend like butter.  My K350 hatch had a .04 in dip in
>it and it flattened out right away.  You just need a bit more weight
>pulling on your hatch.  Gamma used to drip on every dive from the hatch
>seal.  I made an adjustment to tighten the one dog and that cured it.
> How hard is your o-ring?Hank 
>
>On Thursday, December 1, 2016 9:38 AM, Brian Cox via
>Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
>
>Hank,   Is that with out the o ring installed?     Now you've got me
>worried,  I had to give my hatch a little help by sitting on it when I
>pulled a vacuum on it.  I'm not sure why exactly I'll have to check
>again. Brian
>
>--- personal_submersibles at psubs.org wrote:
>
>From: hank pronk via Personal_Submersibles
><personal_submersibles at psubs.org>
>To: Personal Submersibles General Discussion
><personal_submersibles at psubs.org>
>Subject: Re: [PSUBS-MAILIST] conical hatch seat troubles
>Date: Thu, 1 Dec 2016 15:22:15 +0000 (UTC)
>
>Carsten,I can turn it but it is very heavy and wants to wobble in the
>seat or climb out because it is conical.  It is a solution though!   Is
>it necessary though?Hank 
>
>On Thursday, December 1, 2016 4:56 AM, "MerlinSub at t-online.de via
>Personal_Submersibles" <personal_submersibles at psubs.org> wrote:
> 
>
>  Hank can you turn the hatch in the seat ? 
> 3 Peace of sandpater all 120 degree and turning and water dripping
>from a hose or later Piston Paste between hatch and seat ? Making a
>leaver on the hatch and running the hole day around the submarine?30
>Turns clockwise and 30 turns anticclock. Than again. Do you have
>friends liking hard walking? Its a good evening with two friends and
>some sixpacks of beer It was exact that way Emile and I making the
>final seat of a dome seat.  vbr Carsten
>    -----Original-Nachricht-----Betreff: [PSUBS-MAILIST] conical hatch
>seat troublesDatum: 2016-12-01T12:00:56+0100Von: "hank pronk via
>Personal_Submersibles" <personal_submersibles at psubs.org>An: "Personal
>Submersibles General Discussion" <personal_submersibles at psubs.org>   Hi
>All,I have a problem with my conical  hatch seat.  I have discovered
>that I have a .005 in gap between the hatch and seat in two spots.  It
>seems the seat is oval with a gap at each end.  I have no way of
>measuring this other than placing video cassette tape ribbon strips
>between the hatch and seat.  What I do is, I cut the ribbon into 3 inch
>strips, then tape them in place so they are hanging over the seat.  I
>put one every two inches, then close the hatch.  The ribbons are then
>trapped tight in the gap.  if the ribbons can pull out then there is a
>gap.  Sure enough, I can remove one at the front, so I put two ribbons
>on top of each other in that spot and it still pulls out.  I add
>another making 3 ribbons thick and it is tight.  Then I tried doubling
>one ribbon in the front and one opposite in the back and they were
>tight.  The conclusion is that the seat is oval by .005 in at each end.
> I put the hatch back in the lathe and re-faced it, to be sure it is
>not the hatch.  It is the seat, it seems my flange facing machine is
>not perfect-not a big surprise.  This is still very good for a portable
>home made tool.I don't know if this a problem or not, how accurate does
>this have to be?  Will the assembly simply bend?  My feeling is the
>hatch and seat will deform to match under pressure.  To put it into
>perspective, I just measured a hair and that is .01 in. the same as the
>total gap combined.Hank
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