[TowerTalk] Rohn 25 bolts

Ethan ethan at ravenscall.net
Sat Feb 10 11:09:42 EST 2007

K8RI on TowerTalk wrote:
> Most Bolt/fastener distributors will probably carry a grade 5, hot dipped 
> galvanized bolt which I believe are what ROHN uses, but I agree. Why not 
> just call ROHN and purchase what they use. It'll be a few more bucks but 
> this is not a place to economize.
> I would not use cad plated bolts.
> Roger Halstead (K8RI and ARRL 40 year Life Member)
> N833R - World's oldest Debonair CD-2
> www.rogerhalstead.com
Rohn has never, as far as I know, used hot-dip galvanized bolts for 
their 25G towers.  Galvanized bolts would have to have greater 
tolerances to accommodate the zinc, and that likely would weaken such a 
small fastener too much, therefore Rohn chose to use standard zinc 
electroplated hardware which maintains full strength, even though it 
rusts sooner than galvanized.

I do know what the specifications are, having seen them in writing 
somewhere, but also, having pulled the plastic tube of bolts out of many 
a Rohn tower leg and assembling many towers, I know exactly what kind of 
bolts they use.

They are grade 5, zinc-plated, fine-thread, 1-1/2 long, 1/4-28 and 
5/16-24.  This means you measure 1.5 inches from the bottom of the bolt 
head to the tip of the bolt, and the small bolt is 1/4 inch in diameter 
with 28 threads per inch and a 7/16 inch head, while the larger bolt is 
5/16 inch in diameter with 24 threads per inch and has a 1/2 inch head.  
The bolt coating is bright bluish-white, not yellowish or any other color.

This online retailer has lots of information on bolts, sizing charts and 
such, and sells the Rohn-spec bolts.
1/4" and 5/16" bolts:

>> Going all over, looking for replacement bolts, checking into the 
>> properties of stainless, etc. I think we are reinventing  the wheel here.
>> Why not just call Rohn or whoever sells their parts and order the 
>> "official" bolts.  The cost won't be much higher if at all than shopping 
>> around.
>> I'm not the bigget fan of Rohn (being a PIROD user) but lets face it. Rohn 
>> has been the industry leader for over a half century and they supplied the 
>> bolts that would properly do the job. Their engineers knew what they were 
>> doing. If they felt stainless was better, they would have spec'd it and 
>> raised their prices accordingly.
>> Simple... use the OEM parts and you will be fine.
>> Oh yeh, and don't use scrounged / used bolts... you don't know where they 
>> have been!!
>> 73 and be careful on the iron.
>> Mike KM1R

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