Making viewports (was: Visibility / Safety or Safety / Visibility ?)

[Michael B Holt <michaelbholt@juno.com>]

On Tue, 23 Feb 1999 20:33:07 -0500 Jonathan Shawl writes:
>As far as buying view ports I don't know where you can get them. I sent
for
>the report PVHO from ASME to learn how to properly make the lenses.

Tell me more about that report.  
 
>Then I made my own from 1.25 in thick cast acrylic sheet and cut it up
on a 
>saw into octagon shapes. 

Where did you get the acrylic sheet?

(There was a supplier in town who was offering up to one-inch-thick
plexiglass, a few years back, but I need to see what's available now.)

>Then I turned them down round on my lathe. I have 
>the tapered seat design. 

How precise is your machining?   What's the maximum tolerance you 
expect to obtain?   Is that maximum significant?

>I could make some more ASME approved design 
>lenses, but because I am not a ASME certified builder, the lenses would
not be
>technically ASME approved. Do you see what I'm saying?

Yeah, it's like me when I could drive at 14 but no one really cared
because
I wasn't officially checked out.

>If some one used this report, did there own design work, and sent me 
>the material and a drawing, I could do the machining.

Hmmm . . . . .

>That way you are responsible for whatever happens not me, you would 
>also have to make a test rig and test your own lenses before installing 
>them.

What kind of test rig?

>That way I am just cutting a piece of plastic for you and I would not be
the
>one saying it would be ok to use them as view ports. The maximum Dia. 
>that I can turn in my lathe is about 10".

This sounds reasonable to me.

Jon, did you ever think of duplicating the all-clear hull of the subs
that
used hexagonal pieces to make a sphere?   I used to wonder how difficult
that might be.


Mike Holt
--

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