Bill, you have presented probably the best approach. Getting a piece of
aluminum or steel that size and having it machined presents a few problems.
Finding a shop with a milling machine that big is going to be a challenge
in most places. If you do find one, they will likely charge $150.00 per hour
for the milling. Milling one edge will release stresses causing it to warp.
Milling the opposite edge may well warp it back but, chances are, milling
and flipping a couple of times will be needed. Minimum of $300.00 shot.
Milling away material to lighten it will likely make the problem worse
unless done equally on both sides. We're up in the neighborhood of $600.00
now. The idea of grinding a piece of steel presents the same problems. In
addition to that, in my 20 years of machining, I have never seen a grinder
that big though you may find someone with a grinding head on a big mill or
planer. After it is all done, you have the transport and storage problem
Bill mentioned. Do the wood, much more practical.

"Bill in Detroit" wrote in message
...
Jay Pique wrote:

I could probably live with a 32nd over 16 feet. If I did get a 3/8 x 6
x 192" piece of aluminum that was staight, or had it milled straight,
would it stay that way?

Oh ... now you want durability too? ;-)

When you carry / store that aluminum, never let the 'straight' edge face
either up or down without support under it. All straightness will be but
a memory the next time you try to use it.

You might consider getting a section of box channel iron and having it
surface ground square in a machine shop with a big surface grinder. But
I wouldn't. How would I get it back home and down into my basement sop
without losing all that expensive straightness?

Me? If I was going this route I'd probably rip a couple widths off some
3/4" plywood and lap joint / dowel them, using a third section to line
up the joint.

But I'm new here so what do I know?

Bill
--
If God didn't exist, there would be no need for atheists.