When Rudy typed 6061-T8, I also thought that he meant 6063-T8. I just
noticed that DX Engineering does sell 6061-T8. 6061-T6 is tough as nails, I
wonder if the T8 makes it stronger or more brittle. They also sell drawn
tubing up to 3" diameter with a .120 wall which depending on tolerancing may
telescope. When I built the 54' free standing vertical at P40A
http://www.qrz.com/db/p40a I could not find material that would telescope
for the larger sections. I used extruded 6061-T6 tubing and machined them
to fit. My vertical had a 3" diameter bottom and tapered to 1/2" at the
top. It was fairly easy to walk up into the vertical position and held up
for a decade to the constant wind. I agree that a full sized free standing
vertical would require a 4" bottom section.
John KK9A
To:r_bakalov@yahoo.com, towertalk@contesting.com
Subject:Re: [TowerTalk] Choice of aluminum
From:TexasRF@aol.com
Date:Sat, 13 Oct 2012 18:36:45 -0400 (EDT)
Hi Rudy, 6061-T6 aluminum has a yield strength rating the same as 6063-T832
that is sold by Texas Towers and others.
The 6061-T6 costs more than 6063-T832 because of the extra
heating/quenching steps needed to reach the rated yield strength. 6063-T832
reaches the
rated yield strength by work hardening the material in the drawing process.
If you want a self supporting vertical, then you would need to go through
the same process as designing a 80 meter beam element with most of the
material weight left out of the calculations. Just as a guess I would
expect
the
bottom section to be about 4" diameter with a .25" wall.
This is not a trivial structure! Please proceed with caution!
If you want a guyed vertical, there are a number of them that have been on
the air long enough to think about duplicating one. W5UN is one that comes
to mind.
73,
Gerald K5GW
In a message dated 10/13/2012 4:09:30 P.M. Central Daylight Time,
r_bakalov@yahoo.com writes:
I was wondering if anyone can help me select the right material for
full-size 80m verticals. My questions are as follows:
1) metalsupermarkets.com offers 6061-T6 aluminum, but not T8. Is there a
difference between T6 and T8 for my purpose?
2) Should go for the 0.125 or 0.065 wall thickness?
3) Is 1" tubing OK for the topmost segment? Too stiff for the wind at 70'?
Not strong enough?
I am aware that many ham stores offer 6061-T8 tubing, but I do want to buy
it local in VE3, close to my QTH, in 12' lengths (instead of 6') and avoid
shipping complications due to length or clearing customs.
73 Rudy N2WQ
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