Fwd: [TowerTalk] US Tower TB-2US bearing

[Larry Burke WI5A]

Chuck... I have a very similar configuration... TX455 and WARC7 mounted on 
top. I just replaced a 95 pound PRO57 which had been up there for a number 
of years. The WARC7 is much lighter. As I recall there are only one or two 
set screws on mine as well... the bearing is an eccentric collar type. 
Seems to hold just fine.  I have a small instruction sheet from the 
manufacturer (Hub City) that I can type up for you on e-mail (it is short, 
but I am on my way to work). The instruction sheet references two screws. 
Many rotor mfgrs recommend that you put the mast and antenna weight 
directly on the rotor... the thrust bearing then helps contain side-to-side 
movement above the rotor. Sorry I can't crank it down right now to check 
the actual number of set screws.. I may be bringing it down in a couple of 
weeks - maybe sooner - for some antenna work, but that is probably too late 
for your needs.

Thanks for your 1/17/99 RTTY QSO and QSL on 15m and our 11/23/98 CW QSO on 
10m.

Larry WI5A



>X-From_: owner-towertalk@contesting.com  Sun Jun  4 23:22:12 2000
>From: "Chuck Kresge" <du3nxe@mozcom.com>
>To: <towertalk@contesting.com>
>Subject: [TowerTalk] US Tower TB-2US bearing
>Date: Mon, 5 Jun 2000 12:18:57 +0800
>X-Mailer: Microsoft Outlook Express 5.00.2919.6600
>Sender: owner-towertalk@contesting.com
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>
>
>Has anyone purchased and installed a TB-2US thrust bearing from US Tower? If
>so, I would like to know the configuration of the bearing collar that
>attaches to the mast that you received.
>
>I recently received a TX-455 55 foot crankup tower with a TB-2US bearing
>installed. The collar was attached at the top of the tower with a metal
>strap. An Allen wrench was also attached. The collar had ONE 5/16" Allen set
>screw installed. 90 degrees from the screw was a hole approximately 17/64"
>size drilled into the collar about 1/4", which is about halfway through the
>collar.
>
>Unless the laws of physics have been modified, that single 5/16" set screw
>is not going to be adequate to support the weight of my 15 foot mast and
>WARC-7 yagi and EF-140S 40 meter rotatable dipole! It appeared that the
>collar had been incompletely machined and it was intended the collar have 4
>set screws installed.
>
>Numerous email messages to US Tower explaining my problem with the bearing
>collar have gone unanswered. I suspect they figured my tower was the place
>to unload this useless bearing since it was going to be shipped to the
>Philippines where the recipient might not be astute enough to realize he
>received a faulty bearing.
>
>Very discouraging. But fortunately for me I have a spare YAESU GS-065 thrust
>bearing which I will install in place of the TB-2US bearing. After two more
>weeks the cement of my foundation will be cured and I will raise the tower.
>I hope it does not have any defects like the thrust bearing.
>
>Chuck Kresge-DU3NXE du3nxe@mozcom.com
>
>
>
>
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