I have been watching this thread as much as possible since I just bought a Rohn
Tower. And am looking at options for fitting it for
further use.
At this time at least I don't need a thrust bearing because this assembly uses
a Rotor Top section, however, I may need one later
on.
I use to have one on my 48 foot HDX48 years ago when I was still active in
1986. It held a Cushcraft 5 Element fifteen meter mono, 6
Element 10 Meter Mono, 4 Element 20 Meter Mono, a 17 Element for 2 Meters and
strapped a couple of dipoles to the side. Never had
any wind problems or anything else.
I used a HamIV Rotor (rebuilt it myself before mounting) with a Rohn Thrust
bearing on top of the tower. Had no problems for years
in the scorching humidity of South Central Texas in San Antonio.
One would think that after all these years of experience, expertise and success
that Rohn would have it down right. What I mean is
that according to the theory of Name Brand, Top Of The Line, ect ect that they
would be the boys to go to for anything tower
related.
Seriously this sounds bad, what happened, did they get bought out? I remember
when they were the only ones to consider, has
something changed with them I am not aware of?
73 fer nw es gud DX,
QSL VIA: BUR, LotW, e-QSL
Bob AD5VJ(AAR6VM)
Old calls: WY5L/KH3-KE5CTY-N5IET
http://www.ad5vj.com/
Member: CTDXCC, NTCC, STXDXCC
FISTS: # 12637, SKCC# 2369
10X# 37210, FP#-1141
SMIRK#-5177, RARS #-149
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of AB7R
> Sent: Friday, January 12, 2007 5:58 PM
> To: john@kk9a.com; TOWERTALK@contesting.com
> Subject: Re: [TowerTalk] Rohn TB3 or TB4
>
> The thrust bearings at array solutions look very nice and
> have zerc fittings on them. Going to order one for my hg-70HD.
>
> Greg
> AB7R
>
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com]On Behalf Of john@kk9a.com
> Sent: Friday, January 12, 2007 3:55 PM
> To: TOWERTALK@contesting.com
> Subject: [TowerTalk] Rohn TB3 or TB4
>
>
> I bought a Rohn TB-3 four years ago and when I received it
> and turned it by hand and it would often lock up. I returned
> it and got a replacement, which turned a little easier. I
> installed the bearing on my Aruba tower and after several
> months it started to bind. The binding was only noticeable
> when turning by hand as somehow the rotator was able to turn
> the mast. I then sprayed a little WD40 into the bearing and
> it turned easier, however I quickly replaced the Rohn bearing
> with one made by Create.
>
> John KK9A
>
>
>
> To: towertalk@contesting.com
> Subject: [TowerTalk] Rohn TB3 or TB4
> From: "Roger Kissel"
> Date: Thu, 11 Jan 2007 15:08:00 -0500
> List-post: mailto:towertalk@contesting.com
>
>
> So you're all saying that lubrication should not be used with
> a Rohn thrust bearing ?
>
> I just took down a tower that had not been used for quite a
> few years. It had a Triband beam and a TB3. I thought I had
> hit the jackpot.
>
> Until I tried to turn the bearing. It was locked up !
>
> I disassembled everything and took it alll home. When I got
> the bearing into the shop, I put it in the vise and tried to
> turn it. Still couldn't turn it.
> So I removed the allen screw and removed the bearings so I
> could take the races apart.
>
> The balls, by the way, were not shiny. They had a matte
> finish. Once I got the races apart, I could see why it would not turn.
>
> First, the races are aluminum. Poor (No, BAD) engineering
> practice, IMO. The balls, sitting in one place for years,
> wore into the aluminum race and the
> AlO2 that had developed over the years, ground into the
> races. It also ground into the steel balls, giving them their
> matte finish.
>
> The outer race which is the main flange that bolts to the
> tower plate, was worn into a multiple scallop shape. The
> balls sat in those scallops and would not turn.
>
> I don't know if lubrication would have made any difference in
> this case, since the rotor had not turned for so long.
>
> I would imagine that if the race had been filled completely
> (like we used to do with wheel bearings - the roller bearings
> that we squeeeezed the grease
> into) that dirt would not have gotten in.
>
> For the time being, I have built back the bad races with TIG
> and am going to remachine the grooves and use new balls and
> see if I can reuse the bearing.
> If not, I'll put up a STEEL bearing.
>
> I really think the loser is the Rohn engineers who produced
> the TB2, TB3 and TB4.
>
>
> Makes me really wonder why Rohn went bankrupt....
>
>
> RoGrrr
> KC8HZ
>
> _______________________________________________
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