From DASTO@fester.swales.com Tue Jan 30 16:10:20 1996
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From: "Tom Dasto *" 
To: jdotson@belmont.astro.nwu.edu (Jessie Dotson)
Date:          Tue, 30 Jan 1996 17:07:49 EST
Subject:       do's & don'ts
Cc: sean@irastro.gsfc.nasa.gov (Sean Casey), Scc1960@aol.com,
        jdotson@belmont.astro.nwu.edu (Jessie Dotson), Scc1960@aol.com
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Jessie,

Here is the list you wanted.  If I think of anything else, I'll 
update it.


SPARO DOwar (& Don'twar) Ideas

In the following tables are listed specific DO's & DON'T's relating to the 
     design of the SPARO dewar.  
Disclaimer: Items listed below may or may not be meaningful in a Helium 3 system.

DO

1	Utilize vapor cooling
2	Attach shields to vent tube at locations closer to the reservoir than predicted
3	Use thick vent tube attachment plates
4	Align bolt patterns between all "shells"
5	Use metal o-rings (smallest diameter possible)
6	Design o-ring glands for stock rubber o-rings (useful during initial phases)
7	Use as many bolts as can fit in the pattern when sealing components with metal
8	Place o-rings on the "up" side of all components
9	Design with Pro/E
10	Use flathead screws between shields
11	Attach end-support rings to shields to maintain circularity during assembly
12	Build a stable work/assembly stand
13	Try to design an adjustable structure (thermal and mechanical tweaking)
14	Design a shorter/fatter dewar over a longer/skinnier dewar (more top plate real-estate)


DON'T

1	Use small tolerances for frequently assembled components
2	Leave less than 0.1" material in a threaded blind hole
3	Use doublers/rivets on shields
4	Underestimate friction in mechanisms
5	Design without Pro/E


P. S. I was really stretching for some of these!



Tom