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Re: [PSUBS-MAILIST] thru hull fittings
The make lathe tools for cutting internal O-ring
grooves. With the right tool it is no more difficult
then cutting an external groove.
Warren.
--- Thijs Struijs <thijs-struijs@planet.nl> wrote:
> Brian, Alec,John,
>
> I made the drawing. Machining an o-ring grove in the
> fitting seems rather
> difficult to me so i thought instead of making a
> grove in the shaft why not
> do it this way. It's not according the books, but i
> can not imagine why it
> shouldn't work.
>
> John, i am also interrested in your ideas on
> machining internal groves.
>
> Greatings,
>
> Thijs Struijs
>
> ----- Original Message -----
> From: "Alec Smyth" <Asmyth@changepoint.com>
> To: <personal_submersibles@psubs.org>
> Sent: Monday, March 01, 2004 3:53 PM
> Subject: RE: [PSUBS-MAILIST] thru hull fittings
>
>
> > Yes, this is for the drop weight, but no, I didn't
> do what Thijs just
> > proposed. I'm afraid to say I just went with plain
> old grooves on the
> > shaft. The grooves will weaken it a bit, its true,
> but on the other hand
> > the shaft is pretty massive and is supported where
> the grooves are.
> >
> > Alec
> >
> > -----Original Message-----
> > From: Brian Cox [mailto:ojaibees@ojai.net]
> > Sent: Sunday, February 29, 2004 11:28 PM
> > To: personal_submersibles@psubs.org
> > Subject: Re: [PSUBS-MAILIST] thru hull fittings
> >
> > Thijs,
> > If I'm not mistaken I think that is
> what Alec has done.
> >
> > Brian
> >
> > ----- Original Message -----
> > From: "Thijs Struijs" <thijs-struijs@planet.nl>
> > To: <personal_submersibles@psubs.org>
> > Sent: Sunday, February 29, 2004 12:21 PM
> > Subject: Re: [PSUBS-MAILIST] thru hull fittings
> >
> >
> > > I just posted a drawing (or at least i hope i
> did) to Moki files of a
> > thru
> > > hull fitting. It is just an idea for solving 2
> problems: weakening the
> > shaft
> > > and machining an O-ring grove in the fitting.
> Maybe it is a solution.
> > > Have a look at:
> > > http://www.prismnet.com/~moki/subfiles.html
> > >
> > > Greatings,
> > >
> > > Thijs Struijs
> > > The Netherlands
> > >
> > >
> > > ----- Original Message -----
> > > From: "Brian Cox" <ojaibees@ojai.net>
> > > To: <personal_submersibles@psubs.org>
> > > Sent: Sunday, February 29, 2004 7:54 PM
> > > Subject: Re: [PSUBS-MAILIST] thru hull fittings
> > >
> > >
> > > > Ok , so if I'm understanding this now the
> issue here is the strength
> > of
> > > the shaft. If that is the only issue I would
> have to say that it
> > would not
> > > make any difference whether the o ring is on the
> shaft or the inside
> > the
> > > fitting. Since it would be much easier to
> machine a O ring grove in
> > the
> > > shaft and also easier to inspect for burrs and
> put chamfer on the
> > edges of
> > > the grove I submit that putting the O rings on
> the shaft would be more
> > > advantages. If you have to turn that 1/2" shaft
> hard enough so that
> > it
> > > would sheer off then there is some other
> problem. Am I missing
> > something?
> > > >
> > > > Brian
> > > > ----- Original Message -----
> > > > From: "Dan H." <jmachine@adelphia.net>
> > > > To: <personal_submersibles@psubs.org>
> > > > Sent: Sunday, February 29, 2004 10:08 AM
> > > > Subject: Re: [PSUBS-MAILIST] thru hull
> fittings
> > > >
> > > >
> > > > > Brian,
> > > > > No, no Not at all.
> > > > >
> > > > > Either O-rings on the shaft, or O-rings in
> the housing will work.
> > As
> > > far as
> > > > > leaking, it's the shaft to housing clearance
> and the proper groove
> > depth
> > > > > that matter. And yes, hydraulic
> applications do sometimes use
> > O-rings
> > > in a
> > > > > shaft but not as a rule. If the shaft is
> the critical component,
> > the
> > > O-ring
> > > > > grooves are in the housing. Grooves in a
> shaft weaken it.
> > > > >
> > > > > Maybe I didn't explain myself well before.
> What I meant by my
> > earlier
> > > > > posting was, if you groove the shaft, the
> groove diameter, minis a
> > > little
> > > > > factored in for the stress risers created by
> the groove, becomes
> > the
> > > working
> > > > > diameter of the shaft. The weakest point!
> A groove does create
> > stress
> > > > > riser. If you break a shaft with grooves in
> it, it will always
> > fail in
> > > one
> > > > > corner of a groove. A properly designed
> O-ring groove has small
> > radii
> > > in
> > > > > it's corners, but still it's a week spot.
> If you take the same
> > shaft
> > > size,
> > > > > but put the O-ring in the housing, you can
> design around the full
> > shaft
> > > > > diameter.
> > > > >
> > > > > I tried to keep my shaft diameters from
> getting larger then needed
> > > because,
> > > > > as a shaft get larger it takes more force to
> turn when your deep.
> > At 400
> > > > > feet a one inch shaft has 160 pounds of
> force pushing in on it.
> > That
> > > > > creates friction that you have to overcome
> to turn it.
> > > > >
> > > > > Dan H.
> > > > > ----- Original Message -----
> > > > > From: "Brian Cox" <ojaibees@ojai.net>
> > > > > To: <personal_submersibles@psubs.org>
> > > > > Sent: Sunday, February 29, 2004 12:14 PM
> > > > > Subject: Re: [PSUBS-MAILIST] thru hull
> fittings
> > > > >
> > > > >
> > > > > > Hi Dan,
> > > > > > I knew that would draw
> a response ! I really
> > don't
> > > > > follow the reasoning on this. I simply do
> not understand what you
> > are
> > > > > saying. Don't most hydraulics have the O
> rings on the the shaft
> > and
> > > with
> > > > > those we're talking 3000 psi. If I had the
> O rings on the shaft
> > are you
> > > > > saying that I would not be able to turn the
> shaft? And the O ring
> > would
> > > > > leak because there is more stress on the
> corners
=== message truncated ===
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