[TowerTalk] Bearings for Axial Load

[Jim Thomson]

Date: Sat, 15 Jul 2017 19:42:29 -0700
From: Grant Saviers <grants2 at pacbell.net>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Bearings for Axial Load

< One issue I've been told about with rotating towers but never 
<done or seen done is how to replace the bottom bearing without taking 
<the tower down.

<Grant KZ1W

##  On the original RTS setups, they used 3 huge, and long, threaded rods, every 
120 degs, between the mating plates, not quite into each corner.  Then  nuts and washers
on both sides of both plates for each of the 3  threaded rods.   These threaded rods were a
temporary setup..... typ used when the  rotor was at the 40 to 50 ft level.   IE:   Bottom 40-50
feet did not rotate.   But same deal was used with rotor below 10 ft level.   The threaded  rod assy
held the 2 sections of tower together..and dead straight..and upper sections  would also not rotate. 

##  Once guys were all installed... or at least the lower guy wires on the upper sections, then the  3 x temp
threaded  rods could be removed. 

##  For replacement of that  huge bearing at the bottom,  I think the procedure  was to re-install the 3 x rods,  all guys loosened up a bit..and I think
a hydrualic  jack used to lift the upper sections a tiny bit...then rod assys tqed down.   Then bearing removed, and
replaced,    and rev process  done.    The bearings used on the rings were  designed to be replaced..after the fact.

##  On broadcast station base insulators, they use a hydrualic jack to elevate the tower enough to replace the insulator. 
Saw in a really old national geographic  magazine, where a 1200 ft tall  tower, used as part of the  oem    dew line set up, 
used  3 insulators at the base.   1 was cracked badly.  They actually jacked up the entire 1200 ft tower...and replaced all 
3 insulators with one big one.  It was quite the engineering feat at the time....in the late 50s. 

Jim   VE7RF