RE: [PSUBS-MAILIST] fabrication question

[Alec Smyth <Asmyth@changepoint.com>]

Thanks Carsten! 

- Alec

-----Original Message-----
From: MerlinSub@t-online.de [mailto:MerlinSub@t-online.de]
Sent: Monday, May 21, 2001 3:57 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] fabrication question


Hi Alec - I weld flanges 2 inch in thickness and 36,7 inch in
outside diameter to a cylinder 27,5 in diameter and a half inch 
in tickness. I was pretty shure (before) that the weld will not damage 
the flat surface of the flange designed for a flat gasket - 
because of the strong tickness of the flange according to the small
tickness of the cylinder - but ..

.. I was wrong - the surface of the flange is not longer flat 
- and for this reason I will turn the seat ring for the o-ring later in
. 

Make sure that you can machinery turn the seat later - if nessesary ..

> Welding first and turning the whole assembly ... < .. is the better way- 
I did it that way with the propeller shaft hose also - was out of axis
of about 4 mm ( 0,16 inch) of a length of 2,2 m ( 87 inch) after welding
the pipe to the two regulator tank welding strong connections ..  Not
real visible but clear to much for a bearing .. fortunatly I have same
reserve in the material to turn it down to the middle axis :-)

At the moment I am a little afraid that maybe the two knees which
connect 
my main entrance hatch with the spring will damage the hatch flatness
(the o-ring nut is allready in) - for this reason I think I will weld
this strong 
knees only with step-welds.. To prevent rust I will cut out the knees
between 
the short welds. 

1/2 inch is not a visible measuring for a shipbuilder ..

regards Carsten 


Alec Smyth schrieb:
> 
> Lets say a hatch seat ring has a 0.75"x1.5" profile, with the 0.75" being
> the "thickness" and the 1.5" being the width of the seat. Can anyone tell
me
> whether welding it to the conning tower might deform the ring enough to
> cause a seating problem? Surely there's a point when the thickness frees
me
> from worrying about weld stress?
> 
> Welding first and turning the whole assembly is possible, but I wondered
if
> I might skip that extra step.
> 
> 
> thanks!
> 
> - Alec