At 02:38 PM 7/9/98 -0400, Lowell, Mark wrote:
>
>< Any comparison to the very expensive "chromolloy" masts some talk
>< about here?
>
>Why yes, Dave, type 4140 steel that I mentioned is alloyed with both
>chromium and Molybdenum (try saying *that* word 3 times fast! <grin>) and
>is commonly referred to as 'chrome-moly' steel. It can be hardened to many
>different levels.
>
>I forgot to list some other common materials...ummmm lemmesee:
>(Again from Machinery's Handbook, 23rd ed.)
How about some uncommon ones? My ME son tells me that there are some
composite materials that are fantastically stiff in one dimension and
flexible in others. As an example, he cited pole-vault poles, that bend
like crazy but are extremely stiff in torsion. He opines - though not his
field - that composites probably could be laid up to be extremely stiff in
bending, kind of the opposite. Sounds like it would make an excellent boom
or mast, being much lighter than chrome-moly and probably even stiffer and
stronger. It also occurred to me that such stock shapes as composite tubes
may be being made in the aircraft industry, perhaps for use as components
of aircraft structures. Does anyone know? And is the price prohibitive?
73, Pete Smith N4ZR
In wild, wonderful, fairly rare WEST Virginia
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