Sounds like schedule 40 2 inch pipe with ID a bit over 2 inches might do the
job. 73, Dan, N5AR
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com]On Behalf Of Roger (K8RI)
Sent: Tuesday, January 06, 2009 3:46 PM
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] Rohn TB4 Thrust bearing
K7LXC@aol.com wrote:
>
> In a message dated 1/6/2009 2:00:29 P.M. Pacific Standard Time,
> towertalk-request@contesting.com writes:
>
>
>> At one time
>>
> they said to run them dry, but I don't find any recent mention of that.
> There was a thread on this topic last fall that was both pro and con for
> greasing.
>
> There is no con. The 'con' position' was previously stated such that
> since they couldn't find that the manufacturer didn't say not to grease
was that
> it was okay to. The LXC Prime Directive states to "DO what the
manufacturer
> says" and the usually unstated second part of that is to "NOT do what
they
> don't tell you". If they say to do it - do it. If they don't say to do
it -
> don't do it.
>
>
But there were both pro and con *opinions* in the thread
I happen to agree with you in running the bearings dry.
> You don't grease them. It just attracts particles and junk out of the
> air and promotes premature wear. It spins at 1 RPM - it doesn't need to
be
> greased.
>
Agreed.
OTOH I've completely destroyed two TB-3s so far. When I redo the top
I'm going to build a sleeve be it one or two feet long. I'd prefer to
use roller bearings, but that'd mean some lathe time and building in
some seals to keep out the weather.Plus it doesn't need to be that
precise anyway. 2" double lip seals are relatively easy to find and
not at all expensive. BUT a simple rubber cone made from sheet wrapped
and clamped to the mast is more effective and has no low spots to
collect water. The sleeve OTOH is not precision. Plastic or rubber
devices/sleeves can easily be made to weather proof them and a simple
grease zerk at the top and bottom takes care of the lube. That and the
sleeve doesn't add a support surface that may increase the loading on
the rotator, or worse, give it negative loading with temperature
changes. IOW it serves as side support only. Also with the sleeve, minor
rust is not a problem except for appearance. I can add a support block
a few feet above the rotator to hold the mast when working "up there"
What I need is to find about 2' of 2.5" OD DOM for the tube as it needs
to be a nice fit over 2" OD tube.
73
Roger (K8RI)
>
> Cheers,
> Steve K7LXC
> TOWER TECH -
> Professional tower services for hams
> Cell: 206-890-4188
>
>
>
>
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