From: Daniel Fundo 
To: Leftfieldstar{at}aol.com
CC: mbartels{at}efn.org, atm{at}shore.net
Reply-To: Daniel Fundo 


From Dominic DiLeo:

<<... The economy of material use is rather poor and will bet that this
structure could be made substantially more rigid and lighter using tube
stock, I beams and angles.

I fully appreciate machined surfaces but only when they serve a direct
function, but cutting holes out of expensive slab stock and the high
machining costs incurred to lighten an item is a double waste.  >>

Agreed!  According to my Alcoa Product Guide, a 3"x 1 1/2" 6064
T6 channel ("C" channel) has 40% less weight, the same y-axis
stiffness, and 4 times the x-axis stiffness, holes accounted for.

As Tom K. pointed out, I am a bit concerned about the rigidity of the
"trusses" in relation to the mirror support.  There doesn't seem
to be enough material in the secondary supports to keep the diagonal in
position if the beam is bumped.  Almost looks like a big tuning
fork......with all of its vibrational attributes.

However, there is no denying that it is a beautiful piece of craftsmanship!

*****-----
Dan F.
Secretary/MAS
Memphis, TN

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