Hi Jim, thanks for posting that, the 'matrix' as you call it.
I'm curious why you'd make a stainless engine cradle .

In the cost/weight/strength blend and considerations.....
 Something built for brute sense like an engine cradle, would be thicker and
more expensive in stainless, than the equivalent steel piece.
The vanagon engine cross bar is a perfect example....for the
cost/weight/strength balance.....simple steel is called for.

To make the same part in stainless.....stainless is nice for corrosion
resistance, but it's not as strong as mild steel for a given thickness.....
would cost more, significantly more, I'd think, for the same strength. 
Hence you don't see stainless engine cradles anywhere ....

Seems the 'next most rigid light weigh cost effective ' material would be
cast aluminum, and you do see that in car design.....like the diesel engine
mounts for example....light weight, doesn't corrode too easily, not
expensive in mass production ( a factor for you as you are making say, 50 to
a hundred per year, , compared to 50,000 for a manufacturer, so exotic
castings are not justified in small numbers, , leaves you with mild steel
normally, from a cost/ strength viewpoint.  There could even be a few bucks
in saved money there you could pass onto your customers, by using steel
there.  Easier to fab , everything. Cheaper. Etc. 

Anyway, I think what you are doing is fantastic !
Scott 
 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Jim Akiba
Sent: Friday, July 27, 2007 12:37 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Decisions, decisions which conversion-didn't intend to start a
power war

 I just posted the matrix that I started working on long ago(in 06
 actually). I never did anything with it as I was not certain of the
 value without oversight. But now with google apps, if anyone would
 like to help fill it in, and have collaborator access for editing
 please let me know.

 http://spreadsheets.google.com/pub?key=pTRYtmiQuaK3fqBbHuKk1OQ

 Thanks,

 Jim Akiba