[Towertalk] TOWER BOLTS (Was: Help locating freestanding tower)

[n4kg@juno.com]

N4KG anecdotal supporting evidence follows W8JI comment.

On Sat, 15 Jun 2002 "Tom Rauch" <w8ji@contesting.com> writes:
> 
> 
> you dont want grade 5 for a tower, or stainless, stainless is too  
> weak and grade 5 is to hard, theyll break under stress, you want 
> A325  type 1 or 2, its a structural grade bolt, itl  stretch under high

> stress instead of shearing off at the head, trust me ive been stackin 
> iron for a long time   sk-8-er
> 
	W8JI response:

> With free-standing towers, especially those with flange-type joints 
> that is true. 
> 
> Cross-bolted tower joints do not put stress on the bolts, other than 
> modest cutting (shear) pressure! The bolts used in telescoped cross-
> bolted leg joints are far from critical, as long as they are nearly 
> as hard as or harder than the mild steel .050-.125 inch thick legs 
> (that in some towers are welded, softening them further from the 
> heat) trying to "cut" the bolt. 
> 
> Stainless bolts or even unhardened mild steel bolts are perfectly 
> fine for guyed towers with cross-bolted telescoped leg joints. The 
> main concern is rust.  Flanged joints, especially in self-supporting 
> 
> towers, should always use the manufacturer's recommended 
> hardware.73, 
> Tom W8JI
> W8JI@contesting.com 
> 

N4KG:

I agree with W8JI's comment about SS hardware being adequate
for guyed towers.  My 130 ft of Rohn 35 (15 inch wide tower with 
legs identical to R25) was installed using SS bolts from a local
Fastener Supplier.  I went with SS because the supplier had a
good selection at reasonable prices and did not have galvanized
bolts in stock.

When a small tornado passed through my woods, two 70 ft trees
fell on the top set of (1/4 inch) guys, arching the top 30 ft over 
about a foot.  The tower straightened itself after the trees were
removed.  That was at least 5 years ago and the tower is still
standing.  I would probably go with the appropriate strength
galvanized bolts if I were to do it over but obviously the SS
bolts were 'adequate'.

Tom  N4KG



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