Speaking of cable pulley bearings, if you care to replace one yourself,
instead of paying $80 or so for the pulley and bearing, they (the bearing)
can be purchased usually NIB on eBay for $10 - $20 each. You may have to
create an eBay search on your account to find one when it shows up.
One of the more common bearing used is the KP8 or KP8A. Perhaps you can get
the bearing info from your tower manufacturer. Or, you may have to remove
one of your pulleys when you have the chance and see which you have.
Different size pulleys have different size bearing pressed into them.
Removing a pulley requires knowledge on what you are doing. If you are not
mechanically inclined, don't try it. It can be dangerous. But done
correctly, its not difficult and can the pulley can removed safely. You'll
need slack in the cable and blocking one of the tower sections when
lowering the tower is one way to do it. But, if you have a pull down cable,
don't go so far down as to put too much tension on that cable. If you are
working on the bottom tower section, you may have a cable tensioning
spring. Removing tension on the spring might be enough to provide enough
slack to remove that pulley.
Perhaps another way to provide cable slack is to raise the upper tower
section with a come-along. I've never done it that way and not sure if it
will pull up lower section too.
The safest way would be to have your tower laying on the ground or in the
horizontal position.
Again, know what you are doing before you try!
Ray,
N6VR
On Tue, Sep 4, 2012 at 8:43 PM, <NPAlex@aol.com> wrote:
>
> Steve,
>
> Having had one LM-470 crank up cable fail because a pulley bearing had
> rusted and would not turn, and the added stress caused the failure. Sealed
> or
> not here in Florida they get water inside. I also had a frozen bearing on
> my current US 589 tower, fortunately it was on the pull down cable and not
> a
> high risk.
>
> Each of these pulley bearings are of the closed , ball bearing design, but
> have had water intrusion and rusted. Once rusted it is easy for the
> bearing balls to become misshapen and then freeze the pulley - I am
> sticking
> with my recommendation as it has happened to me.
>
> Norm W4QN
> ===========================================
>
> In a message dated 9/4/2012 1:57:44 P.M. Eastern Daylight Time,
> K7LXC@aol.com writes:
>
> > So my recommendation is to regularly lube the cables, and rigorously
> grease the pulley bearings. Because the pulley bearings are deep within a
> 'sheave' I recommend drilling a small hole (1/8") next to the pulley
> mounting
> bolt so that a lubricant can be squirted directly into the bearing
>
> It's probably not necessary. For years, UST (and others I'm sure) have
> used pulleys with pressed-in sealed bearings so no attention is needed.
> OTOH if your pulleys have bushings instead, periodic lubing is a good
> practice.
>
> Cheers,
> Steve K7LXC
> TOWER TECH
>
>
>
>
> _______________________________________________
>
>
>
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