Re: [PSUBS-MAILIST] Viewport Question.

["James Frankland" <james@guernseysubmarine.com>]

Hi Dan/Peter.

Yes, i did leave it a bit tight.  But i wanted to ask people what they thought so i deliberatly left it.  I can always machine more out, but it would be difficult to add some back on!

I think i'll probably machine a bit more out.  Maybe to 1.5 mm ?

I didnt really want to have to machine the lenses as i believe they need to be stress relieved by annealing after machining is complete.  It would be much nicer if they just slot into place when they arrive.

Perhaps i should get the lenses organised so i can have a trial fit.

Thanks for the advice as always its appreciated.
Regards
James

----- Original Message -----
From: Dan. H. [mailto:jumachine@comcast.net]
To: personal_submersibles@psubs.org
Sent: Tue, 11 Dec 2007 08:30:47 -0500
Subject: Re: [PSUBS-MAILIST] Viewport Question.

James,

Also be aware that acrylic thickness isn't constant even when cut from the
same sheet.  It may be wise to have your acrylic parts in hand before
machining your rings.

The only way to get a truly good fit between the lenses and housing rings is
to do a final machining after the rings are welded into the hull, but most
of us don't have that option.  Anything else is just doing the bet you can
do with what happens after welding and the tolerance of the acrylic you get.

Hey!  Nice web site!
Dan H.
----- Original Message -----
From: "James Frankland" <james@guernseysubmarine.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, December 11, 2007 6:02 AM
Subject: [PSUBS-MAILIST] Viewport Question.


Hello All.

Quick question regarding viewports tolerance.

Ive started machining and have done 2 at the moment.  Ive machined the depth
of the bore to be exactly 1.25 inches as per the plans, and the inside
diameter i have machined to 8 inches plus a clearance of 0.5 mm to allow the
lense to drop in.  (sorry, the plans are imperial but we're metric here, so
its a bit of both).

Im not making the acrylic lenses myself, i will buy them (probably from
psubs store).  Assuming they come in exactly at 8 inches OD, as things are
they should slot in nice and tight.

But Dan H mentioned to me that he got some slight distortion on the ports
after welding.

So the question is, do you think 0.5 mm clearance is enough?  Obviously i
cannot alter the ports once they are welded in, and don't want to have to
start machining the lenses, they must fit.

You can have a look here as usual.  Some of the text titles are wrong.  I'll
change them later.

http://www.guernseysubmarine.com/index_files/Page7497.htm

Any thoughts?

Thanks
James




----- Original Message -----
From: Jay K. Jeffries [mailto:bottomgun@mindspring.com]
To: personal_submersibles@psubs.org
Sent: Mon, 10 Dec 2007 20:16:42 -0500
Subject: [PSUBS-MAILIST] Digital Multi-Frequency Scanning Sonar

Here is what looks like a great scanning sonar for a PSUB.  If it is priced
like some of their other products, it should be a great deal.



http://www.imagenex.com/html/881l_imaging.html



R/Jay





Respectfully,

Jay K. Jeffries

Andros Is., Bahamas



A skimmer afloat is but a submarine, so poorly built it will not plunge.








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