I've used both drawn 6061-T6 and 6063-T832, the yield strength and other
parameters are essentially the same. The yield strength for both is
around 35-40k psi. Many other tempers of 6063 are not as strong.
See Table 3-1 Yield Strength of Aluminum and Steel Alloys, pg. 3-8,
"Physical Design of Yagi Antennas." It shows both at 35,000 psi. A
downloadable scan of my book is at
https://www.dropbox.com/s/hmhkeofz0igrg1e/Physical%20Design%20Of%20Yagi%20Antennas%20D%20B%20Leeson%20V2.pdf?dl=0
For another picture, see
https://www.makeitfrom.com/material-properties/6061-T6-Aluminum/ and
https://www.makeitfrom.com/material-properties/6063-T832-Aluminum/
You can always reinforce with inner tubing, see "Strengthening the
Cushcraft 40-2CD," QST, Nov. 1991, pp. 36-42,
https://k7vc.com/402cd.html See also Section 11.3.1 of Physical Design.
73 de Dave, W6NL/HC8L
On 8/12/24 1:58 PM, john@kk9a.com wrote:
I am not a mechanical engineer or a metallurgist but I believe that the
tensile strength and yield strength for 6061-T6 and 6063-T8 are nearly
identical. I used to buy 6061-T6 for all of my homebrew Yagis from Shapiro
Metal Supply and certainly did not pay $60-$80 for 72" pieces. Lately I use
the 6063-T832 that DX Engineering sells. I really would be surprised if
Cushcraft used 6061-T6, their aluminum always seemed soft to me.
John KK9A
Michael W1ECT wrote:
A couple of years ago we had a big ice storm here that damaged my
Cushcraft 40-2CD (2-el "shorty-forty") antenna. It's been sitting
it in the basement for quite a while and I've finally gotten around
to refurbishing it.
The worst damage was to the innermost element sections (4) which were
badly bent and need to be replaced. I see that DXEngineering carries
the appropriately sized tubing: 1.250" OD, .058" wall, and 72" length.
Their price is reasonable at $21 each but the alloy is 6063-T832 and I'm
wondering if this will do the job. I did some searching around the web
for 6061 tubing and found the prices to be around $60-$80 each!
Mike - W1ECT (b1 at xmlog.com)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|