[TowerTalk] rotor shelf
Robin Midgett
rmidgett@edge.net
Mon, 19 Apr 1999 21:46:14 -0500
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Hi Mark,
I have a supply of SS U-bolts of the 1/4-20 variety which fit nicely around 25G
tower legs. They are a Chicago Hardware standard issue U-bolt. If you cannot
locate a source for Chicago Hardware in your area, I'll be happy to supply you
the quantity you need. I also have SS 1/4-20 lock nuts & Keps nuts.
At 12:17 PM 4/19/99 -0700, you wrote:
>
>Greetings Towertalkians,
>
> I began pre-assembling (on the ground) the top section of a Rohn 25
>tower I am installing soon. I am using standard sections with a flat
>top adaptor. I intend to install two rotor plates in the top section,
>one for a second thrust bearing (to aid with future rotor servicing)
>and one for the rotor itself.
> Big surprise when I found out that the rotor shelf/accessory shelf
>only fits in two places: 1) Joints between tower sections and 2)
>inside the top plate adaptor. In both cases, these are places where
>there is no bracing. I want to have my rotor about halfway down the
>section to give it a longer moment arm, and install the second
>bearing just above it. I don't want to waste 10 feet of good mast
>just to have the rotor down at the next section joint.
> After a little head scratching, I grabbed the hacksaw and made one
>triangular cutout in the center of each side of the shelf. This
>allowed the shelf to fit in the middle of the tower section, halfway
>between horizontal braces.
> Another surprise! the flange of the Rohn TB-3 is too large to fit in
>a location that is halfway between two horizontal braces. <jeez>
> More head scratching....
> Three more cutouts, one in each side of the shelf, off center, let
>me install the shelf just a few inches below a horizontal brace, and
>the TB-3 fits, as well. After drilling the hole pattern for it, of
>course.
>
> Has anyone else had this problem, and how did you solve it?
>
>One more thing. The flat top adaptor (ordered from Texas Towers)
>apparently does not come with a set of bolts. Got to get an extra set.
> The U-bolts that came with the rotor shelves (and tower sections,
>for that matter) were thinly plated, not galvanized. They don't look
>like they could take exposure to the weather for long. I was thinking
>of replacing them with stainless versions.
> Will these parts benefit from cathodic protection from the existing
>galvanizing of the tower itself? Would I be wasting my money on
>replacements?
>
>Thanks for your comments,
>
>--...MARK_N1LO...--
>
>_______________________________________________________________
>Get Free Email and Do More On The Web. Visit http://www.msn.com
>
>--
>FAQ on WWW: http://www.contesting.com/towertalkfaq.html
>Submissions: towertalk@contesting.com
>Administrative requests: towertalk-REQUEST@contesting.com
>Problems: owner-towertalk@contesting.com
>Search: http://www.contesting.com/km9p/search.htm
73,
Robin E. Midgett KB4IDC EM66se
rmidgett@edge.net
1/2 of the Award Winning NT4L Rover Team
http://kq4tv.aprs.net/vhf/vhf.html
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<html>
<font size=3>Hi Mark,<br>
I have a supply of SS U-bolts of the 1/4-20 variety which fit nicely
around 25G tower legs. They are a Chicago Hardware standard issue U-bolt.
If you cannot locate a source for Chicago Hardware in your area, I'll be
happy to supply you the quantity you need. I also have SS 1/4-20 lock
nuts & Keps nuts.<br>
<br>
<br>
<br>
<br>
At 12:17 PM 4/19/99 -0700, you wrote:<br>
><br>
>Greetings Towertalkians,<br>
><br>
> I began pre-assembling (on the ground) the top section of a Rohn 25
<br>
>tower I am installing soon. I am using standard sections with a flat
<br>
>top adaptor. I intend to install two rotor plates in the top section,
<br>
>one for a second thrust bearing (to aid with future rotor servicing)
<br>
>and one for the rotor itself.<br>
> Big surprise when I found out that the rotor shelf/accessory shelf
<br>
>only fits in two places: 1) Joints between tower sections and 2)
<br>
>inside the top plate adaptor. In both cases, these are places where
<br>
>there is no bracing. I want to have my rotor about halfway down the
<br>
>section to give it a longer moment arm, and install the second <br>
>bearing just above it. I don't want to waste 10 feet of good mast
<br>
>just to have the rotor down at the next section joint.<br>
> After a little head scratching, I grabbed the hacksaw and made one
<br>
>triangular cutout in the center of each side of the shelf. This
<br>
>allowed the shelf to fit in the middle of the tower section, halfway
<br>
>between horizontal braces.<br>
> Another surprise! the flange of the Rohn TB-3 is too large to fit in
<br>
>a location that is halfway between two horizontal braces.
<jeez><br>
> More head scratching....<br>
> Three more cutouts, one in each side of the shelf, off center, let
<br>
>me install the shelf just a few inches below a horizontal brace, and
<br>
>the TB-3 fits, as well. After drilling the hole pattern for it, of
<br>
>course.<br>
><br>
> Has anyone else had this problem, and how did you solve it?<br>
><br>
>One more thing. The flat top adaptor (ordered from Texas Towers)
<br>
>apparently does not come with a set of bolts. Got to get an extra
set.<br>
> The U-bolts that came with the rotor shelves (and tower sections,
<br>
>for that matter) were thinly plated, not galvanized. They don't look
<br>
>like they could take exposure to the weather for long. I was thinking
<br>
>of replacing them with stainless versions.<br>
> Will these parts benefit from cathodic protection from the existing
<br>
>galvanizing of the tower itself? Would I be wasting my money on
<br>
>replacements?<br>
><br>
>Thanks for your comments,<br>
><br>
>--...MARK_N1LO...--<br>
><br>
>_______________________________________________________________<br>
>Get Free Email and Do More On The Web. Visit
<a href="http://www.msn.com/" eudora="autourl">http://www.msn.com</a><br>
><br>
>--<br>
>FAQ on
WWW:
<a href="http://www.contesting.com/towertalkfaq.html" eudora="autourl">http://www.contesting.com/towertalkfaq.html</a><br>
>Submissions:
towertalk@contesting.com<br>
>Administrative requests: towertalk-REQUEST@contesting.com<br>
>Problems:
owner-towertalk@contesting.com<br>
>Search:
<a href="http://www.contesting.com/km9p/search.htm" eudora="autourl">http://www.contesting.com/km9p/search.htm</a><br>
</font><br>
<div>73,</div>
<div>Robin E. Midgett KB4IDC EM66se</div>
<div>rmidgett@edge.net </div>
<div>1/2 of the Award Winning NT4L Rover Team</div>
<a href="http://kq4tv.aprs.net/vhf/vhf.html" EUDORA=AUTOURL>http://kq4tv.aprs.net/vhf/vhf.html</a>
</html>
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--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm