On 5/19/2010 12:38 PM, Jorge Diez - CX6VM wrote:
> Hello,
>
> I use to have a TB25 thrust bearings
> http://gmesupply.com/product_info.php/cPath/268/products_id/55960
>
> How about this one? Something to take care in the future with this model?
>
I have two of these and have had three TB-3's or which one is still good.
The TB25 has a much better fit and finish and is much smoother than the
TB-3, BUT it doesn't have as heavy a ratings as the TB-3. When you put
them side by side the TB25 is noticeably of much lighter construction
than the TB-3.
How well it will stand up compared to the TB-3 in the real world of ham
radio? I don't know, but by *appearances* (which is no real indicator)
it will not take the abuse that the TB-3's do on a regular basis and
keep on kicking.
73
Roger (K8RI)
> Wich commercial thrust bearing seems to be better than otherts?
>
> Thanks!
> Jorge
> CX6VM
>
> -----Mensaje original-----
> De: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] En nombre de N2TK, Tony
> Enviado el: Miércoles, 19 de Mayo de 2010 01:23 p.m.
> Para: 'Jim Thomson'; towertalk@contesting.com
> Asunto: Re: [TowerTalk] thrust bearing lubrication
>
> I am not saying the TB3 is a high quality product. But I have been using one
> for 30 years on the same tower. The only change I made was to replace the
> bolts with stainless steel. The mast is 2" and 32' long with 8' in the
> tower. On the 24' sticking out of the tower I have had combinations of
> antennas from initially a 105, 155, 205, 402 (the antennas sure flopped
> around in high wind). Then a C31, MAG240N, Warc7, EF-606 combination. Now I
> have a MonstIR.
> And the 80' of Rohn 45 tilts over at the base. That puts a nice side load on
> the TB3 with the antennas ganging down. Sure it makes noise if I turn it by
> hand at a higher rate than 1RPM. Never had it apart. Seems to keep on doing
> what it was designed for - keeping the mast centered and taking the load off
> the rotator.
>
> Maybe there are better thrust bearings. But will stay with my dry TB3 for a
> while yet.
>
> 73,
> N2TK, Tony
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim Thomson
> Sent: Wednesday, May 19, 2010 10:00 AM
> To: towertalk@contesting.com
> Subject: [TowerTalk] thrust bearing lubrication
>
> Date: Tue, 18 May 2010 11:56:14 EDT
> From: K7LXC@aol.com
> Subject: Re: [TowerTalk] thrust bearing lubrication
>
> In a message dated 5/18/2010 8:39:28 A.M. Pacific Daylight Time,
> Brahmangou@aol.com writes:
>
>
>> Unlubricated bearings? Maybe the reason you are wearing out the races.
>>
> I use Moly grease on all of mine, no problems yet. Every bearing needs
> lubrication, even old windmills from 100 years ago have oilers, and
> windmills
> only turn at about 75 rpm. Where I live dust and dirt above 50 feet is not
> a
> problem, maybe in West Texas or Arizona the big dust storms could deposit
> enough to make a difference.
>
> The Rohn thrust bearing isn't a conventional bearing in the sense
> you're talking about above. It turns at 1 RPM. The manufacturer says does
> not
> say to grease it.
>
>
> The LXC Prime Directive says to "DO what the manufacturer
> says."
>
> ### it's a good thing I don't follow that rule. All my F-12 ants
> would have fallen apart by now.. amps blown up, xcvr's that
> are below par.. and require loads of mods etc, etc.
>
>
>
>
> In this case, do not grease the Rohn TB.
>
> ## Ok.. so what does rohn suggest you do then.... replace the poorly
> engineered TB3/4 every 6 x months ??
> IMO... it's a way over priced piece of junk. Now, if you take it all apart,
> remove the balls... smooth out the race.. lube both the raceS and the
> balls.. and perhaps put a rain cover over the top of it....it will last a
> lot longer.
> If that set screw was replaced with a grease nipple fitting, we would not be
> having
> this conversation.
>
> ## use no grease in the wheel bearings on your car.. and poof, they won't
> last
> 2 x days. It baffles me why manufacturer's keep making the same junk
> year
> in and out.... like TB-3/4's... W2AU baluns, BN-86 baluns, toy rotor's,
> lousy
> coax connectors you can't solder to, xcvr's with 15 % thd 1.5 watt audio
> amps,
> lousy headsets, yagi's that fall apart, yagis that have gross torque
> imbalance,
> rotor mast clamps that slip, and/or loosen.... muffler clamps with useless
> sheet metal saddles, muffler clamps that rust. The list is a mile long.
>
> ## 'do what the manufacturer says' .... sometimes.... but only if they have
> engineered the product correctly. A buddy just bought 190' of Rohn 55g.
> None of the sections fit..and all of em..so far have had to be re-drilled.
> Quality control has gone out the window.
>
> Later..., Jim VE7RF
>
>
>
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