I have had 2 tb-3's at 150' above peru mass for 22 years without touching
them. At least 4 others also up for periods from 20 to 7 years, never a
failure here. Never a drop of lube.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of K8RI on Tower talk
> Sent: Saturday, July 08, 2006 02:19
> To: towertalk
> Subject: Re: [TowerTalk] Mast and Thrust Bearing questions
>
>
>
>
> > Chris: Rule of thumb is 1/3 of the mast inside the tower...it is a rule
> > you should follow. Rohn TB3 thrust bearings will last a very long time
> > if you DONOT lubricate them. If you do, then expect failure. They are
>
> Mine lasted about 5 years and it's completely shot. OTOH it was beat to
> death from having a lot of antennas well above it. When the antenna work
> is
> done and the TB-3 replaced (with another TB-3) the top arrays are not
> going
> back up. Just the tri-bander and the 7L 6-meter Yagi.
>
> > designed to run dry and unless you rotate the beams constantly ie 24
> > hours a day every day then it should last you a lifetime. It is a good
> > idea to put a boot on the mast to keep water out of the bearing....look
> > for a rubber collar in the plumbing section. If you don't have ice
> > don't worry about it.
> >
> > A second lower thrust bearing is a good idea if you ever need to pull
> > the rotator. It need not be a thrust bearing tho. You want to
> > eliiminate side movement is all. If you use a second TB3 then do not
> > tighten the capture nuts except when you are lifting the mast to pull
> > the rotator. It is almost impossible to get two thrust bearings aligned
> > such that there is no twist. Leaving the lower one loose keeps lots of
> > trouble from happening.
> >
> > A second rotator plate with the mast running through the hole and a
> > piece of oak with a hole drilled about 1/8 inch larger than the mast and
> > bolted to the shelf will do the trick for far less money. When you need
>
> That's a good idea. The only things I'd do differently would be to soak
> the
> Oak in hot oil for a few hours and to make the hole a "slip fit". What'd
> really work nice would be to do it in a "pressure cooker" that could be
> sealed off while it was cooling. This would create a vacuum as it cooled
> and
> drive the oil deeper into the Oak when the air was let in. OTOH if you
> have
> a wife this might be better done in secret, but she still might wonder why
> things out of the cooker are now tasting strange.
>
> I belive Ash is another good wood for bearings.
>
> Roger Halstead (K8RI and ARRL 40 year Life Member)
> N833R - World's oldest Debonair CD-2
> www.rogerhalstead.com
> > to pull the rotator just put a U bolt and saddle on the mast and resting
> > on the top of the oak to keep it from slipping down while the rotator is
> > out.
> >
> > Good luck and do it all safely. 73 bob de w9ge
> >
> > Christopher J Galbraith wrote:
> >
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|