[TowerTalk] Rohn TB3 Bearing

[Mike Gilmer, N2MG]

The several Rohn TB-3 bearings that I have used usually
seem a little rough when turned by hand, but I have not
had them bind (see below).  They come with no grease 
inside, no grease fitting and no hole for one.  Since the 
bearings are not sealed, I doubt very much they are 
designed to be greased since the grease would both 
leak out and what didn't would get contaminated quite 
easily.

With the Rohn design, I have found the bearing binds 
when its set screw (used to access the ball bearings and 
take it apart) is screwed in too far or not far enough.  
Also,  I've heard the bearings can also bind if the 
aluminum races' surfaces become rough (I've never seen 
this personally).

Mike N2MG


WW5I wrote:
> About once a year I need to lower the tower, lock it down 
> and get an extension ladder and climb up
> with a grease gun and regrease it.  It sometimes takes 
> nearly an entire small tubes of grease from my greasegun 
> before it oozes out and I turn the bearing as I'm squeezing 
> the grease gun handle to distribute the grease throughout 
> the bearing. The bearing turns easily when greased. Even 
> when I forgot one year and waited two years to regrease the
> bearing, it still turned with little effort.
> 
> KK9A wrote:
> >
> > I purchased a Rohn TB3 bearing from Texas Towers 
> > which did not turn very smoothly and often times jammed 
> > when turning it by hand.  I exchanged it for a different one 
> > (thanks Gerald) which seemed a little better.  The new TB3
> > was still not smooth, but at least it turned without jamming.  
> > I installed it on top of a 70' tower in Aruba and after 
> > several months I checked it and this one also jambs when 
> > turning it by hand.  The rotor so far has been able
> > to turn it.   On my Rohn 65 tower in Illinios I have a Create 
> > bearing on a 3" mast which I am  very happy with, 
> > unfortunately I don't believe that they are still available.  Is 
> > the Rohn bearing junk and is there something better
> > that will fit a Rohn 55 tower?