Re: [ATM] aluminum poles

[Mark Holm <mdholm@telerama.com>]

Bill wrote:
> Looking for customers of Texas Towers' 6063-T832 Drawn Aluminum Tubing
> that can shed some light on the performance.  I'm no metalurgist, but I
> understand that the 6063 is not as strong as 6061.  Is the 6063 acceptable
> for truss poles?  I would be doing 1.25" x .058" for a 24" f/4.
> Thanks in Advance,
> Bill
> 
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam protection around 
> http://mail.yahoo.com 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 
> 
The most common 6061 tubing is 6061-T6
Properties are at
http://www.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061T6

Properties for 6063-T832 are at
http://www.matweb.com/search/SpecificMaterial.asp?bassnum=MA6063T832


Material strength is rarely an issue for aluminum tubing for truss
poles.  Telescopes just don't load their trusses heavily enough for
inherent strength to matter.  Stiffness is more important to telescope
truss design.  Material stiffness is given by the Modulus of Elasticity.
 For these two alloys, as for most aluminum alloys, the modulii are
essentially identical.  Thus, strength and stiffness are both pretty
much non issues as far as alloy choice goes.  Stiffness is much more
affected by tube diameter and to a lesser degree by wall thickness.

For truss tubes, corrosion resistance (good for both 6061 and 6063 as
far as I know), machineability and perhaps formability are more
important.  Formability is important for those designs that crush the
ends of the tubes to make flat sections for fastening.  I've never done
it.  I think I recall that those that have recommend heating the tubing
before crushing.  I do not know whether there is an advantage to 6061 or
6063 for that purpose.

I've got a tent with 6061 poles that are still going strong after 20
years.  The nylon fly is getting a bit weak due to sun exposure, but the
poles are nearly as good as new.

-- 
Mark Holm
mdholm@telerama.com

_______________________________________________
ATM mailing list http://www.atmlist.net/