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Re: [TowerTalk] Lateral load bearings

To: TOWERTALK@contesting.com
Subject: Re: [TowerTalk] Lateral load bearings
From: Pete Smith N4ZR <n4zr@contesting.com>
Date: Fri, 29 Jun 2012 05:58:57 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Rick, keeping in mind that your rotator is an extremely low-speed 
device, slop really is not an issue - for that matter, neither is 
friction, within reason.  If it were me, I would have someone fabricate 
a plate with a small piece of tubing mounted in the middle, sized to fit 
loosely over your mast, and mount that above your rotator.  Another 
option (used on the side-mounted tribander in my stack) is a piece of 
the hardest available plastic sheet, about 25mm thick, with a hole bored 
to fit over your mast.  Then bolt the plastic to  plate that mounts in 
the tower above your rotator.

I have had these solutions in place on my tower for 17 and 12 years 
respectively, and there is no sign of significant wear or friction on 
either.

73, Pete N4ZR
The World Contest Station Database, at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at 
reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000 and
arcluster.reversebeacon.net, port 7000

On 6/28/2012 7:43 PM, Rick Kiessig wrote:
> I'm looking for a lateral load bearing to use with the upper support plate
> for the mast on my tower.
>
>   
>
> Array Solutions carries one that's intended to work with a 2" mast (2 1/16"
> opening), though it's not designed for outdoor use (they suggest painting it
> before deploying). My QTH is near the ocean, so that's a concern.
>
>   
>
> The brackets on the antenna can be configured to support either a 50mm or
> possibly 60mm mast. The readily available piping in ZL in this size range is
> generally 48.3mm outside diameter (I'm looking for 50mm material, but it's
> hard to find/custom); mostly steel, though aluminum seems to be available
> too. The antenna is 29 kg, with a 0.67 sq m wind load.
>
>   
>
> Since the bearing will be used to support lateral loads, and not as a thrust
> bearing, how much slop is reasonable between the outside of the mast and the
> inside of the bearing?
>
>   
>
> Are there other commercially available alternatives for bearings like this?
>
>   
>
> Also, for a relatively light weight antenna like this, what sort of wall
> thickness should I use for the mast?
>
>   
>
> 73, Rick ZL2HAM
>
>   
>
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>
>
>
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