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## Re: [TowerTalk] How to stiffen a mast

 To: richard@karlquist.com, "Barkey, Patrick M." Re: [TowerTalk] How to stiffen a mast Jim Lux Mon, 31 Jan 2005 14:30:49 -0800
 At 12:12 PM 1/31/2005, Rick Karlquist wrote: Stiffness (not strength) is proportional to the quantity: OD^4 - ID^4. In your current case, this is 2.5^4 - 1.5^4 = 39 - 5 = 34 ```The best you could possibly do with an aluminum insert is to emulate a solid rod, in which case the stiffness would be higher by a factor of 39/34 which is a 15% increase in stiffness. I believe steel is about 3 times stiffer than aluminum, so a solid steel rod would get you a factor of 49/34 or 44%. ```Or, even a steel tube.. the 4th power making tubes almost as stiff as a solid bar works for all materials.. A thin wall steel tube is probably stiffer than a solid aluminum bar of the same OD (or weight). Rick N6RK ```Barkey, Patrick M. said: > I've been using 24 foot, half inch wall, 2.5 inch OD aluminum masts > on all of my towers for quite a few years, with no failures or real > problems. During the recent ice storm, however, a couple of them > flexed a little more than I'd like to see (they've since sprung back). > > Now that I have the opportunity to think this over, I am wondering > if it would be of any value to try to add a little more stiffness to > the existing mast by driving something into the hollow center. > I've got a 1.5 inch ID hole to work with - perhaps some pipe or > solid rod could be driven into it?``` _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. ```_______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ``` _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. ```_______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk```
 Current Thread [TowerTalk] How to stiffen a mast, Barkey, Patrick M. Re: [TowerTalk] How to stiffen a mast, Rick Karlquist Re: [TowerTalk] How to stiffen a mast, Jim Lux <= RE: [TowerTalk] How to stiffen a mast, D. Scott MacKenzie [TowerTalk] How to stiffen a mast, Shannon Boal