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.
http://www.boltdepot.com/
1/4" and 5/16" bolts:
http://www.boltdepot.com/product.aspx?cc=6&cs=7&cm=80&cd=95
http://www.boltdepot.com/product.aspx?cc=6&cs=7&cm=80&cd=96
>
>
>> 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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