[Antennas] Fasteners

2002年6月26日 13:51:10 -0400

Hi Dave,
A pretty good though provoking comment....
Bolting the sections together makes for a better mechanical connection which
means better conductivity to handle the THOUSANDS of AMPS from a lightening
strike. Lack of bolts will eventually result in some corrosion between the
sections where they'll rub together - yes the sections will
move/vibrate/etc., from ground vibrations, cars rolling down your street,
and the wind. If you ever get to look at a seismograph's output strip,
you'll see that the ground is vibrating ALL THE TIME. The bolts hold a good
metal to metal contact and provide at least a small area that's never
exposed to the weather.
Better mechanical connections make the tower feel more stable if you ever
have to climb it.
If the tower ever comes down accidentally, and your insurer or the opposing
counsel uncovers the fact that you did not follow the manufacturer's
recommendations, then you'll be held to be negligent! In that case, someone
else will get to own your radios....
---------------------------
The people who make the bolts, washers, and nuts have to send their kids to
school, buy groceries, pay their ARRL and AMSAT memberships, AND have the
ability to buy the products and services that you or your employer provides
...... You pay them, so they can pay you - the principle of the American
economic engine.
===============
I'm sure you'll also get a lot of other input on this.
73
Frank
 ._._.
----- Original Message -----
From: "Dave Shrader" <[email protected]>
To: "Mike J Maloney" <[email protected]>
Cc: <[email protected]>; <[email protected]>
Sent: Wednesday, June 26, 2002 12:47 PM
Subject: Re: [Antennas] Fasteners
> 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ドル.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 2002年6月24日 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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