Tower lift cable replacement - stainless steel or galvanized?

[KM1H]

To be honest I dont think highly of US Towers and their service and information. After all they are in the business of selling cables at a high profit. Ive had several battles with them over the years when I was doing tower and antenna work.

The 3 years is a best case install in Podunk Hollow, near salt water they say 18 months. That should tell you something about the quality.

As far as grease I suggest any doubters visit a marine enviroment such as a  boatyard, Navy ship, etc. Its time consuming to do it right and climbing ability is required for a tower.

[WA1GFZ]

Yea Carl look at any cable spool on a crane. it is well covered with grease. I would think it would lubricate the strands from sheading coating.
I bet SAE 90 would work well because it would flow

[KD6VXI]

I know in the tow industry, we lubed the wire ropes in our winches on a regular basis, and they came prelubed from the factory.

I don't know what it was that we used, but the guys that did take care of their winch cables on a regular basis had little to no issues, and the guys that didn't have lots.

FWIW...  Maybe a phone call to a decent tow yard could shed some light on the subject?


--Shane
KD6VXI

[kg8lb]

Stainless wire rope (cable) is generally more flexible than Galvanized wire rope. The strength of either in this case sems quite adequate. The flexibilty quality of SS alone makes it better suited for rolling over drums and pulley work.

  BTW, WD-40 is really a poor rust preventative. There are asphaltum based open gear / wire rope materials that are far better up to the task of adding weather resistance.  Like Carl said, getting dirty is not life altering.

[W2VW]

Yup those silly manufacturers haven't a clue. Better off getting info from some guy on the internetz.

What with all the resume posts it's obvious who really knows what


And Water Displacement 40 will dissolve your concrete tower base and kill all the kittens in the neighborhood.

This place is turning into QRZ.

Work smarter, not harder.
 

[WBear2GCR]

I do not know the "answer(s)".

But, elevator cable is designed to be "stretchy" and has a non steel core.

I think aircraft cable too has some stretch designed in.
My understanding is that some designs are intended for no stretch, and some are.

I suspect that in the case of wire rope used in cranes and in tow trucks, it is run back and forth so many times that failure due to friction on the bends points is greater than failure due to water corrosion. So, they go for the lube.

Glenn up in Maine runs those big cranes, he might know the story on the wire rope they use on them?

I know that LPS3 displaces water... not sure if the "bike (motorcycle) chain lube" sprays do the same trick or not. They both go on thin-ish and dry like a grease...

I had some special Shell Oil Co. grease in a tube for grease guns that was positively water proof - try to get the stuff off ur hands!

The crank up tower cable/rope needs to more or less work under static conditions, but still make sharp bends when called upon... that means to me a high strand count. The way the "lay" is done may be important too...

You also have to watch out for electrolytic corrosion... even ground currents...

</end core dump>  

              _-_-bear

[kg8lb]

The cable lay and core is quite critical and best related to the application. Yes, by all means consult the manufacturer. My very general comments were in regard to the garden variety SS and Galvanized wire ropes at the local supply houses VS the common galvanized stuff.  The SS cable most refer to as "Aircraft" is usually supplied with a lay that is more flexible.  The galvanizing by nature tends to stiffen the cable as well as add friction when drawn over pulleys.  Usually the higher tensiles are with the slower twists and the higher pitched twist tends to be more compliant. I was not offering a final decision just a few guidelines.  


As far as checking with the Mfgr this wouls apply to outdoor protectants as well.
The people who make wire rope protectants know their stuff.  WD-40 will indeed displace water, for a VERY short time. WD-40 is little if anything more than mineral spirits ("Stoddard Solvent" and a very light Naphtenic base oil. )  Readily washed and weathered, WD-40 is hardly worth the cost, let alone the effort of application. If you really don't want the asphaltum base genuine wire rope lube , consider LPS "TKX" It too "displaces moisture" and leaves behind a much more effective protectant film. Similar products are made by other companies , such as "Boeshield" developed by Boeing to protect metals from corrosion.

 Then again 2200+ posts has to trump an under 500 poster  

[W1ATR]

Jet Lube WLD (Wire Line Dressing) is the way to go. It's specifically made for wire line on cranes and tow trucks, etc. Get it thru marine suppliers, or google for you desert folk.

[KA0HCP]

Real wire rope that is lubricated has a sisal or hemp core which absorbs the lubricant and allows it to wick outwards as the cable is flexed.

Aircraft cable is not intended to stretch... The last thing you want is to turn the wheel or push the pedal and have the controls fail to move because the cable stretched.

Personally, I would spend the money on aircraft cable that is higher quality, Stainless Steel and more flexible.

[kg8lb]

 Is this tower mechanically secured in place when hoisted by a secondary device or are you relying on the cable alone to do that ?

[W1AEX]

If this question is directed at me, the EZ-Way 60 foot - 3 section tower rests on its safeties after it has been cranked to whatever level you wish to set it at. The only time the lift cable carries a load is when the tower is being raised or lowered.

When raising the tower, the safeties automatically snap in and out as each rung passes over them. When lowering the tower, the spring-loaded safeties are manually retracted by a rope attachment and as you crank the tower down, you keep tension on the rope. If a failure occurs in the lift cable system, simply let go of the rope and the safeties will close and block the "uncontrolled" descent. It works fine as long as you quickly release the rope, which I did when my cable broke back in 2008. It dropped about 10 inches and the safeties caught it. I believe that Pete's tower is quite a bit larger than mine, and I could easily envision the scenario he experienced if the safeties didn't close quickly enough to catch it right away.

I learned quickly how to limit the ascent and descent to one section at a time, which makes things much simpler, and only places the full load on the cable when the mid-section is lowered. That has worked out very well with my tower and simplifies control of the safeties.

I actually found a PDF copy of the original EZ-Way manual for my tower, and they recommend an annual greasing of all the skids, pulley surfaces, hinge points and the lift and tilt cables. So Carl, your advice is the same as what the manufacturer recommends. As someone else in the thread mentioned, marine grade grease would most likely be best. I have a couple of friends who work at boat yards, and I know they have boat lifts and all kinds of heavy machinery that uses galvanized cable so I'm going to hit them up for advice. I'm still pondering which galavanized cable to run with, as the cable that came with it is only described as 5/16 inch galvanized cable. The stuff that's out there now seems to have many different strand configurations, so I'm still looking into it.

73,

Rob  

[Jim, W5JO]

Rob, just pick the strongest 5/16 galvanized cable.