[TowerTalk] G-1000DXA failure with lower mast clamp

[Barry N1EU]

Thanks for responding Chuck.  I'm on rented property, so I need to use
the AB577 and a lower mast adapter type rotor installation.

Isn't there any way to prevent the bolts from working loose like they
did?  Better type of lock washer or ????

Barry N1EU

On Tue, Dec 27, 2011 at 2:29 PM, Chuck <w5pr at swbell.net> wrote:
> Hi Barry,
>
> Glad you didn't have damage to the beam.  I don't know much about the 3el
> Steppir, but that seems like a lot of antenna for a mast mounted rotor. The
> antenna wobbles back and forth, loosening the bolts. A stick of Rohn 25 with
> a rotor shelf might serve you better.  The weakest point will fail.  If the
> bolts drop out when the rotor is on a shelf, it just twists.  As for this
> rotor, I think I would be ok with using it.  Three bolts should hold it and
> it looks like you could still catch a few threads on the fourth.
>
> Good luck,
>
> Chuck W5PR
>
>
> ----- Original Message -----
> From: "Barry N1EU" <n1eu.barry at gmail.com>
> To: <towertalk at contesting.com>
> Sent: Tuesday, December 27, 2011 8:16 AM
> Subject: [TowerTalk] G-1000DXA failure with lower mast clamp
>
>
>> My G-1000DXA rotor came completely unhinged from its GC-038 lower mast
>> clamp and left my 3-el Steppir and attached rotor dangling from the
>> attached cables.  It appears that the attachment bolts on the bottom
>> of the rotor came loose and fell out.  Please see photo at
>> http://n1eu.com/g1000.jpg
>>
>> The cast aluminum fractured at one of the four threaded holes on the
>> rotor bottom.  At first I thought this might be the cause of failure
>> but on further thought, I would guess that the other 3 bolts came
>> loose and fell away and this fourth bolt was the last to stay attached
>> and this caused the aluminum fracture.  Any comments on whether this
>> seems correct?
>>
>> I'd also appreciate comments on why this happened in the first place
>> and how to prevent a repeat.  The rotor was assembled to factory
>> instructions with lock washers.  Instead of using anti-seize on those
>> four bolts, perhaps what is really needed is loctite?
>>
>> Does the motor casing need replacement and if so, is this a fairly
>> easy job to do myself?  There's still about half the threads on the
>> one hole that suffered the fracture.
>>
>> Thanks & Happy Holidays,
>> Barry N1EU
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