[Antennas] Fasteners

Wed, 26 Jun 2002 12:47:41 -0400

I have what may seem to be a dumb question.

My Rohn 25 uses GRAVITY to hold the sections together. 

The upper section telescopes over the lower section by about 10 inches
(maybe 8 inches). The bolts are installed after the sections are already
mated. If no bolts are installed, my antenna will still be standing
because gravity takes the vertical loads, not the bolts. [It is guyed].
Now, if gravity fails, like an earthquake, and my Rohn sees a negative g
force, who cares?

My question: What is the purpose of the bolts since they are not load
bearing elements in the design?

Deacon Dave, W1MCE

Mike J Maloney wrote:
> 
> According to Marcia at Rohnnet.com,  the 25JBK joint bolt kit for 20Gand
> 25G sections are $1.60 each and includes:
> 
> 3-bolts 1/4-28 by 1-1/2" Grade 5, Zinc plated
> 3-bolts 5/16-24 by 1-1/2" Grade 5, Zinc plated
> 3-nuts 1/4-28 hex zinc plated
> 3-nuts 5/16-24 hex zinc plated
> 
> Much of their other fasteners are tagged "hot dipped galvanized", but the
> above simply zinc plated, perhaps a cold process.   Dont know why they
> use fine thread, unless that be typical for Grade 5 bolts?   The higher
> price may be for the zinc coating of grade 5 bolts, perhaps not a common
> practice?
> 
> Marcia can give you the nearest distributer, contact her at
> [email protected]
> 
> 73, Mike
> 
> On Mon, 24 Jun 2002 16:16:48 -0400 "A10382" <[email protected]> writes:
> > There is no substitute for quality fasteners....
> >     Get the SAME (SAME meaning IDENTICAL) ones speced by the tower
> > manufacturer and DO NOT SKIMP....
> >         Same grade
> >         Same size
> >         Same thread (and a lock nut if speced)
> >         Same washer & lock washer and nuts as speced
> >         Some manufacturers spec a torque setting for a reason
> > Buying from the tower manufacturer directly may cost a bit more, but
> > may
> > save you a lot of headaches in the future...  Almost every tower
> > will
> > eventually need to come down.  It's easier to unscrew a bolt than
> > cut it
> > with a torch!
> > -------------------------
> > Stainless steel:
> >     IS NOT rust proof, just very rust resistant
> >     Can very in strength and quality
> >     Can gall - you may need to use some sort of anti-electrolysis
> >         compound, especially if within 20 miles of salt water.
> >     Is usually not as strong as similar grade carbon steel bolts
> >     Imported bolts & nuts are frequently mis-labeled as to grade
> >     Same is true of units of unknown origin
> >     Lowes and Home Depot stress price!  Read what you will into that
> > -------------------------
> > 73
> > Frank
> >
> >  ._._.
> >
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> >
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> 
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