OK thanks Roger.
I see now that they are really reducers and not bushes hence the material
that they are made of.
I have put a mast up through the Rohn 25 top piece in the past and it worked
perfectly for many years.
Mark N1UK
----- Original Message -----
From: "Roger (sub1)" <sub1@rogerhalstead.com>
To: <towertalk@contesting.com>
Sent: Wednesday, 17 November, 2010 7:55 PM
Subject: Re: [TowerTalk] question on thrust bearing
> On 11/17/2010 4:46 PM, Mark Robinson wrote:
>> There are bushings available to go inside the Rohn top section
> Not really needed unless the mast is notably smaller than the sleeve.
> I might go as far as wrapping the mast that will be inside the sleeve
> with PVC sheet to serve as a bearing/protection for the mast. A real
> bearing isn't needed.
>
> 73
>
> Roger (K8RI)
>> http://www.3starinc.com/rohn_25ag_45ag_section_tower_bushing_r-tb50.html
>>
>> http://www.3starinc.com/rohn_25ag_45ag_section_tower_bushing_r-tb75.html
>>
>>
>> Mark N1UK
>>
>>
>>
>>
>>
>>
>> ----- Original Message -----
>> From: "J.Gordon Beattie, Jr., W2TTT"<w2ttt@att.net>
>> To: "'Alex Malyava'"<alex.k2bb@gmail.com>; "'towertalk'"
>> <towertalk@contesting.com>
>> Sent: Wednesday, 17 November, 2010 4:19 PM
>> Subject: Re: [TowerTalk] question on thrust bearing
>>
>>
>>> Alex,
>>> Naw...it will be fine if your mast is going through the top section
>>> sleeve.
>>>
>>>
>>> Thanks& 73,
>>> Gordon Beattie, W2TTT
>>> 201.314.6964
>>>
>>>
>>> -----Original Message-----
>>> From: towertalk-bounces@contesting.com
>>> [mailto:towertalk-bounces@contesting.com] On Behalf Of Alex Malyava
>>> Sent: Wednesday, November 17, 2010 8:13 PM
>>> To: towertalk
>>> Subject: Re: [TowerTalk] question on thrust bearing
>>>
>>> Reviving this, 3 years old, subject...
>>>
>>> I am about to install 30' of Rohn 25 tower with MQ-26 (5 HF Bands 2
>>> element)
>>> on it rotated by Yaesu G-450.
>>> I understand that antenna itself is pretty light and it will never
>>> become
>>> anything bigger than MA5B, so it is an easy job for the rotator..
>>> The top section of tower is "Rohn 25 top section"... I am planning to
>>> use
>>> 4'
>>> long "military surplus aluminum green mast" for an antenna mast.
>>>
>>> How exactly I skip thrust bearing step? Do I just feed antenna mast
>>> through
>>> that top pipe and that's it?
>>> Wouldn't it be scratching and squeaking up there?
>>>
>>> Thanks,
>>> Alex K2BB
>>>
>>>
>>>
>>>
>>> On Thu, Dec 20, 2007 at 12:32 AM, Dino Darling<dino@k6rix.com> wrote:
>>>
>>>> A thrust bearing provides two functions...
>>>>
>>>> 1. Vertical load support (not really the right bearing for this
>>>> application for most thrust bearings).
>>>> 2. Lateral support (exactly what most thrust bearings were designed to
>>>> do).
>>>>
>>>> The simple answer to your question is NO, as the vertical load of the
>>>> MA5B is minimal. The lateral support is an advantage and will
>>>> protect the aluminum from long term wear.
>>>>
>>>> If you can afford the bearing, buy it, but its not a "concern" in
>>>> THIS application.
>>>>
>>>> "This is just MY opinion, I could be wrong."
>>>>
>>>> Dino
>>>>
>>>> At 07:08 PM 12/19/2007, Mikemedic130@aol.com wrote:
>>>>
>>>>> I will be looking to add a cushcraft m5ab mini beam (35lbs, and 3.35sq
>>>>> windload) along with a
>>>>> yaesu g-450a rotor to my 7-40 universal aluminum tower. Question is
>>>> should I
>>>>> be concerned
>>>>> with using a thrust bearing? I wont be looking to add anything more
>>> later
>>>>> since I have a small
>>>>> city lot and want to be nice to my neighbors. I currently only have a
>>>> 2meter
>>>>> vertical on the tower now.
>>>>> I guess I am asking do I really need a thrust bearing or not? Any and
>>> all
>>>>> replies would be appreciated.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Thanks mike kc8unr
>>>>>
>>>>>
>>>>>
>>>>> **************************************See AOL's top rated recipes
>>>>> (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004)
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> TowerTalk mailing list
>>>>> TowerTalk@contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> No virus found in this incoming message.
>>>>> Checked by AVG Free Edition.
>>>>> Version: 7.5.503 / Virus Database: 269.17.4/1189 - Release Date:
>>>>> 12/18/2007 9:40 PM
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> No virus found in this incoming message.
>>>>> Checked by AVG.
>>>>> Version: 7.5.503 / Virus Database: 269.17.4/1189 - Release Date:
>>>> 12/18/2007
>>>>
>>>> Dino - K6RIX
>>>> dino@k6rix.com
>>>>
>>>>
>>>> --
>>>> No virus found in this outgoing message.
>>>> Checked by AVG.
>>>> Version: 7.5.503 / Virus Database: 269.17.4/1189 - Release Date:
>>> 12/18/2007
>>>>
>>>> _______________________________________________
>>>>
>>>>
>>>>
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>>
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>
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