Re: [TowerTalk] How to apply lube to HDX589

[Grant Saviers <grants2@pacbell.net>]

Good point on the bearings, particularly if they are ball bearings. Even 
without moisture, sustained non-rotation under load causes the oil film 
to breakdown and fretting/corrosion degrades the race and balls.  Just 
like rotators, frequent movement can replenish the ball to race 
lubrication as the balls rotate and thus enhance the life of the 
bearing.  Moving a tower down/up enough to cause a full turn of all 
pulleys would do it.
With "positive pull down" towers, it might be very difficult to not 
overload the "up" or "down" cable segment unless the locks take no load 
unless a cable fails.
Bigger sheaves are better.  see 
http://www.loosco.com/index.php?page=pulley-diameter    Just for yuks, I 
measured the main winch cable & sheaves on my HDX589. 1/4" dia  7x19 
cable on 3.25" (est) bottom turning sheave, or a tread/wire ratio of 13, 
well below the Loos recommended "critical minimum" of 18.   So UST is 
(IMHO) counting on a very low duty cycle, no regular oscillation (see 
the 35:1 minimum ratio for aircraft cables, which include a life safety 
factor)  and 3 year replacements in order to push the cable life design 
guidelines. google "sheave diameter vs cable life" for other references.
Another set of facts that inform the periodic lubrication of cables 
discussion.
Grant KZ1W


On 6/17/2013 7:45 AM, Patrick Greenlee wrote:
> Ken, From whatever cause, when a cable fails it can be dangerous and 
> expensive. Some failures take place when the tower is not being raised 
> or lowered. Irrespective of the cause of this static failure, if the 
> tower sections were "safed" then damage and danger would be averted.
> My current tilt-over/crank-up has only one movable section and my 
> current refurb action includes adding a lock to take the strain off 
> the cable and the pulley (which I am changing out for a larger 
> diameter.) I'm not an ME either but I think keeping the pulley 
> bearings loaded all the time can't be good for their life span.
> By increasing the pulley diameter I hope to reduce wear on the cable 
> making the turn.
> 73,
>
> Patrick AF5CK
>
> -----Original Message----- From: Ken Beals
> Sent: Sunday, June 16, 2013 5:58 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] How to apply lube to HDX589
>
> Been following this thread with interest even though I donb
>
> Here is a question for the MEs in the group from a decidedly 
> non-mechanical EE: Why would bthe life of the cable? Since the only 
> wear mechanism I see is the flexing of the strands and the internal 
> friction when the cable bends over the pulley when moving. I can only 
> relate a stationary cable to those used on suspension bridges. Those 
> seem to last a long time. So I canbadvantage of section locks with 
> respect to cable life.
>
> I installed towers for a while when I was much younger and I remember 
> that Tri-Ex had an option to add locks to both guyed and self 
> supporting crankups They were different since their guyed towers 
> raised one section at a time rather than all sections equally as a SS 
> tower does.
>
> Ken K6MR
>
>
>
> From: Doug Turnbull
> Sent: bTo: 'Patrick Greenlee', towertalk@contesting.com
>
>
> Chris,
>
>   In my experience there was a single brake at the lowest and therefore
> stationary level.   This counterweighted flap merely takes the strain 
> from
> the lowest wire rope and most importantly from the winch.   Some of us 
> may
> add additional stops by carefully climbing the tower and inserting steel
> bars on heavy duty rectangular cross arm bracing - obviously such a 
> tower is
> not lowered in a storm.
>
>   At this QTH one such tower is stayed as per the manufacturer's
> specification - my additional rest / brake between the second and third
> section are additional.   Imagine the problem which might occur with a 
> five
> section tower using strings to release multiple brakes.
>
>    Removing the entire weight of the upper sections from the winch and
> lowest rope though makes good sense.
>
>    I am not recommending my approach to anyone else.   Great care is 
> taken
> when inserting the additional steel bar between the second and third
> sections.   The larger tower has three sections which are forty foot long
> and the manufacturer insisted on stays.   I did not intend to ever 
> depend on
> the wire rope when stays increase downward loading.
>
>    Why a crank up then.   It make is much easier to work on the 
> antenna and
> greatly reduces climbing.   I have a bad back and it is not wise for 
> me to
> be up top.   Fact is these days I use a rigger.
>
>                73 Doug EI2CN
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
> Patrick Greenlee
> Sent: 16 June 2013 12:51
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] How to apply lube to HDX589
>
>
>
>
> *******************
> If upper sections also have locks, how is the disengagement cable that
> operates the locks managed?  Since the tower gets taller, there would 
> be a
> lot of cable that needs to play out as it goes up.  How is that kept from
> tangling up?
>
>
>
> Chris
>
> *****************
>
> Chris, I have a rag sailor background and we lived aboard our sailboat 
> for 9
> years.  As you can imagine, minding all the running rigging, ground 
> tackle,
> etc. is not a trivial task and is important to get right and can be life
> threatening when fouled up.
>
> A UV resistant very open weave cloth bag to hold the tail of a line 
> (one per
> line) can be real handy. Rain water will not collect in it and permits
> moisture to dry out.  You just stuff the long line tail into the bag 
> in FILO
> fashion (First In Last Out) and when withdrawn from the bag it virtually
> always comes out freely with no tangles.
>
> I can think of hands free systems to take up the slack and pay it out
> automatically but they look like they were designed by Rube Goldberg.
>
> Patrick AF5CK
>
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