Mark you are pretty correct, if indeed your sheave is good and either as
a precaution or real need you are wanting to replace ONLY the bearing/s
in these sheaves these exact bearings are available and at what can be
relative inexpensive, seems like <10.00 each. We had this very
discussion here several months ago and a name associated with a real
vendor was offered up, i did write to him and he responded yes he felt
he had ample stock [800 or so on hand] and proffered a price .
Now the dumb part i save it [information] just forgot where i save it,
but i will look and find it, but again not terribly expensive, but yes
these are pressed into the respective sheave and then peened, staked, or
dimpled to the sheave body, with the idea the the bearing does not turn
solo inside the sheave.
So your effort would be to press out the effected or desired bearing and
press in the new ones, and i would encourage you to just do all of them,
while there are more than you think at first glance its a small price to
pay for the security and additional life expectancy of this important
aspect of your tower.
I will search again and find the contact and address and post it here..
best and 73: mac/mc w5mc
On 9/6/2019 9:47 AM, Robert Harmon wrote:
Mark,
Since you are replacing the wire rope I would check the bearings while the wire
rope is removed before installing the new wire rope.
If they rotate smoothly without any roughness than they are fine. They are
sealed aircraft bearings and are pressed into the sheaves.
Easy to replace with a bench vise or a shop bearing press. I recabled my
HDX589MDPL last year and found 4 pulley berings that were
rough and I replaced them. The pulley sheaves themselves were fine. US Tower
will not sell the bearings separately. You will have to
buy the pulleys with bearings and they ask a horrible price for them. If you
decide to replace the bearings yourself, email me and I will give
you info on the bearing part number and the supplier I used.
Bob
K6UJ
On Sep 6, 2019, at 12:03 AM, Mark Hammond <k7hph@q.com> wrote:
Hello Steve and all that responded:
Mine is real damage to the wire rope. Where I live in Utah, we periodically get very
high winds coming off the eastern mountains (110 MPH Plus). We lose trees, roofs,
buildings, freeway signs, and even rail road cars and semi-trucks will turn over. Most
times the weather forecasters give their high wind warnings early enough that I can
retract the tower before the winds get bad. However, sometimes the wind speeds are
more than the forecasters anticipated and that’s when the trouble begins.
I have an MD75 Motor Drive Unit that I use to raise and lower the tower. When I
need to lower the tower after the high winds have started, I try to time the
lowering process in between the wind gusts. Sometimes, when slowly lowering the
tower between gusts, a wind gust will suddenly hit the tower and the sections
will momentarily stop going down. The MD75 does not instantly stop letting out
cable when I hit the ON/Off Switch. So, when the gust lessens, the tower
sections will drop until the slack in the cable is taken up. They will only
drop a few inches, but that is enough to flatten the cable where it is starting
to roll onto the winch. So, this year, I decided that it was time to replace
the cables and remove the flat spots. I ordered the cables directly from US
Tower for the HDX555. I have a SteppIR DB18E and an M2 2800 winch at the top of
the tower.
I bought the tower with the hand winch. But later on, decided to go with a
motor Drive Unit. I wanted the MDP750 because of the Positive Pull-Down
feature, but was told by US Tower that the MDP750 cold not be installed in the
field; hence the MD75.
Another question is should I replace the pulley’s also? The pulleys look fine, but
I’m not sure about the bearings.
Thanks,
Mark, K7HPH
From: k7lxc@aol.com <k7lxc@aol.com>
Sent: Thursday, September 05, 2019 3:25 PM
To: towertalk@contesting.com; k7hph@q.com
Subject: Re: [TowerTalk] Re-Cabling a US Tower HDX555
I am planning to re-cable my US Tower HDX555 tower this year. Does anyone
in the group have any suggestions or "Do's and Don't's" that would help me?
I already have the cables that I bought from US Tower.
Just curious. What's the compelling reason for changing out the cables?
I've worked on dozens of crank-ups over the years and I've only seen one where
the cables were bad enough that they needed to be replaced.
The 3 reasons for doing it are real rust, real damage to the wire rope or
excessive broken strands. Which ones apply to your tower?
Cheers,
Steve K7LXC
TOWER TECH
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