[TowerTalk] Is Rohn TB3 Thrust bearing OK to use with "flat spots" on bearings?

[K8RI]

On 5/28/2013 10:52 AM, Joseph or Ruth Patrick wrote:
> If the bearing races are good then you could just replace the bearings.
> You should be able to buy them at most bearing supply houses. The top of a TB-3
> just lifts off and the bearings spill out everywhere.

If that TB3 is like mine this could be a bit misleading.   On mine you 
have to remove an Allen set screw from the inside. Then rotate the 
bearing to get the balls from the race out of that hole. the top will 
not lift off until the last ball is out.

It's a good idea to do this over a baking pan with sides at least an 
inch or two high, or as Joe says in a Tupperware dish.

However it would be unusual for the bearings to be out of round. It's 
possible, but usually the TB3s an 4s  wear from setting in one place for 
a long time which wears pits in the races.  You have SS balls in an 
Aluminum race which means the race is much more likely to wear than the 
balls.

When you get it apart, the race should have a lot of white or gray 
powder in it from wear, Clean this powder out carefully.  I use a paint 
brush with the bristles cut to about an inch long and a vacuum cleaner. 
  A you can just take the races out doors and use an air hose to blow 
them out, but the key is "out doors"  Otherwise you have that Aluminum 
powder getting into everything.

If the races have a series of indentations worn in, there's not a lot 
you can do.  If small, I'd not worry about them, but if they feel 
pronounced, it's time to pitch it.  Maybe someone on here has figured 
out how to repair them.

The grease or dry argument has been going on for years.  I leave 'em 
dry, but I think some one recently had ROHN tell them to do what the wanted.

BE CAREFUL with the races.  I've had them wear to the point where the 
edges are like razors and you can easily get hurt when they are that bad.


Nuther nasty storm going through...Time to shut down.

73

Roger  (K8RI)

  Put the bearing in a piece
> of Tupperware to catch the bearings. As I recall the bolts are not stainless.
> They do have a point on one end and a square head. Just take it apart, If the
> races are good then get new bearings. and put it back together. NO GREASE. The
> bolts could probably be galvanized or stainless. Just use the proper
> installation for whatever type you use. Grade 5 or up.It's been awhile since I
> have looked at one so correct me if I'm wrong. Maybe you even have the bearing
> one your bench. Much easier to work on Good Luck
>   73 DE K4XZ Joe Patrick
> God Made Man
> Sam Colt Made Them Equal
>
>
>
>
> ________________________________
> From: John W <xnewyorka at hotmail.com>
> To: TowerTalk <towertalk at contesting.com>
> Sent: Tue, May 28, 2013 10:12:07 AM
> Subject: [TowerTalk] Is Rohn TB3 Thrust bearing OK to use with "flat spots" on
> bearings?
>
> I have an old Rohn TB3 that came with a used tower I bought. Cosmetically it
> looks good and spins without any unusual noise, but it feels like the bearings
> are somewhat oval in shape instead of round. It's hard to explain, but it's
> almost like a sort of ratcheting effect, like there is a little notch every few
> degrees, so that it almost 'clicks' into place, but without a clicking sound.
>
>
> I haven't tested it with a load, but I assume it would probably spin OK with
> only a very small increase in friction.
>
>
>
>
> Can it be used like this, or does it need to be repaired?  If it needs to be
> repaired, how does it come apart and where can I obtain replacement bearings for
> it?
>
>
>
> On a related note, is it recommended to use stainless bolts for the set screws
> that hold the mast in place, or galvanized?  (The originals are gone.)
>
>
>
> Thanks,
>
>
>
> John
>
> W2ID
>
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