Tower lift cable replacement - stainless steel or galvanized?

[W1AEX]

I'm no metallurgist, but I'll bet there are people here in this forum who have some expertise or experience in this area. I acquired my used 1960's era EZ-Way Crank-up and Tilt Over tower back in 1987. It had the original lift cable still installed, which EZ-Way called 5/16 inch galvanized aircraft cable. It was very corroded in many places, so I replaced that in 1988 with 5/16 galvanized wire rope from Texas Towers and that held up well until 2008, when it started to show evidence of corrosion. I replaced that with another run of 5/16 inch galvanized wire rope, which promptly rotted out in 3 years. Obviously, corrosion resistance varies with this stuff. At any rate, I'm thinking that stainless steel 5/16 inch aircraft cable might be a better (safer) way to go, but I wonder about the tensile strength of stainless steel vs. galvanized wire rope.

Stainless steel 5/16 inch aircraft cable sells for about $2.50 per foot vs. $0.50 for 5/16 inch flexible galvanized wire rope, and the tower uses about 80 feet of it. It makes me wonder what others are using with their crank-up towers. Any comments?

[WD8BIL]

Well Rob, ifn ya gots the funds, go with the CABLE.
Leave the ROPE for hanging dipoles.

[Todd, KA1KAQ]

I've got a 45-50 foot EZ-Way still sitting up in VT, Rob. I'd STRONGLY (no pun intended  ) suggest using cable for the lifting/tilting functions. That's what I used to replace it after cleaning and painting. There's a lot of tension on that cable as you know. The chances of injury or damage from having marginal or rotted wire rope snap is just too great IMO.

As far as the little flipper lock mechanism, even nylon rope works fine for that. Can't wait to get mine down here, that wonderpost base sure makes installation easier.

[KD6VXI]

People have heard of the winters that my towers and antennas have gone through.

I use stainless cable for everything outdoors here that I can.  After asking a few other people with towers (and inspecting some old ones on abandoned structures here in the area) I figured it was better to go the right way the first time.

I did have some problems with the SS cable binding up in the 'rollers'...  They where factory crappy fiber things.  I replaced them with real pulleys and no more problems.

The only real problem I have no is the tower binding up if I forget to drop it BEFORE a storm...  If it gets any ice load on it, then I have to manually pull the tower down instead of gravity doing it's job.  I'm wondering  / considering doing a run from the crank to the bottom of the top section, so it's crank up AND down.

--Shane
KD6VXI

[w4bfs]

whichever one you decide on you need to know its tensile strength ... I bought some 1/8 inch stainless cable rated at 400 lbs .... I think the 5/16 should be MUCH higher .... use yer (advanced) high school physics to figure static load in the cable then apply appropriate safety factor (X3) or so

[Jim, W5JO]

I am not sure there is a thing such as galvanized aircraft cable, but do an internet search for wire roap specs.  I believe you will find that 5/16 will hold much more than you need.  Certain sites give specification for all types.  Anything over 2K lbs is probably more than enough.

[W1AEX]

Thank you all for the advice. I think stainless steel cable is probably the wisest way to go. I'm going to call a few tower dealers and see what they sell as replacement cable for their crank-ups to get an idea of what kind of ratings they recommend.

Todd, isn't that "wonder post" amazing? I love the system, but I'll tell you what, standing under there and winching the tower over to it's full tilt position is kind of a terrifying when you realize the amount of weight on the hinge pin. Hope that sucker stays strong!

:O)

[Todd, KA1KAQ]

I had to replace the pin in mine, Rob. Think the fellow used a piece of threaded rod since that's all we could find handily in the shop that night. Should replace it with the proper material some day.

That hinge plate is pretty heavy duty, and has a huge glob of weld on it. The overall mechanics of it make me a bit nervous, if only because of the large amounts of force on so few moving parts and any given time. Always kept a piece of pipe next to mine to stuff between the tower sections in the event things got hung up. That last thing you want is to be losing digits when things free up suddenly. I've notice that it tends to get hung up all around when you don't manipulate it through its range of motion with some regularity.

The post is great, though I wouldn't want to have to move or remove it too often!

[Pete, WA2CWA]

I have an EZ-Way RBZ-75 3 section crank-up/tilt-over tower with a motorized crank-up winch. Installed it in 78. The motorized winch, which came from US Tower (uses a 1 HP motor) was installed in 2001. The tower originally came with a hand-crank up/down winch. Late last year, tower was fully nested, started crank-up, got about 3 to 5 feet up when the cable guiding/lifting the most inner section broke due to steel cable rot. The mechanical brake stopped the downward motion but not before it took out completely one rung and mangled another one on the most inner section. The EZ Way manual just called them "galvanized steel cables". I believe for this tower there were at least two different cable diameters. The motorized winch I bought included 1/4 inch steel galvanized cable which worked fine over the main pulley. I like the additional protection since this cable is lifting both inner sections. I think the original cable was 3/16 inch. Sometime in the next several weeks, a tower person and his crew will be here to replace all the cables with stainless-type cables, welding new rungs where needed, and doing a total inspection of the tower especially all the weld points around the tilt-over section.

The original design of the EZ-Way tower requires that you stand under the tower as you tilt it over since it used a hand-crank mechanical winch. I went over to Grainger and bought an AC operated clutch-driven motorized winch that has a 10 foot umbilical cord to control the motor's operation. There's nothing more intimidating/scary then standing under/close to a 1000+ pound tower as you're cranking it over. The welder/tower person will also fabricate a new mounting plate for this winch.

This tower does not use the "wonder ground post". I forget the actual size of the hole I dug (neighbors thought I was digging to China), but there's over 6 yards of concrete and rebar in that base.

The tower has made it through a number of hurricanes, Nor-easters, and an earthquake over the years in great shape.

Tower fully nested:



Tower at about 45 feet extended:

[ke7trp]

I had this same question on my hygain crank up.  I got the engineering documents from MFJ for my Hygain tower.  The document was a civil engineering test on the tower.  It showed that the cable only has a max of 750lbs on it and the cable used was 7000 lb rated.  All of the math is in the document. 

I was going to order some cable from this place when the time comes:

http://www.wwewirerope.com/aircraftcable/

[The Slab Bacon]

Rob,
       I vote for the S/S cable for another good reason. It will last pretty much forever. As we are getting older, how many more times are you going to be able to  or do you want to climb the tower to replace the rotted wire rope............. 

Just my $.02 worth   

[KM1H]

Any steel cable should be greased before installing and regularly maintained. Getting your hands dirty is not a life altering experience

[Jim, W5JO]

If you choose to go the cheap route, your local hardware store probably stocks cable that will work.  One here has everything from 3/16 to 5/8.  Like Carl says, just keep a thin coat of grease on it.

[W2VW]

A good WD-40 spray every 6 months is a lot better than grease.

At least older grease.

[Pete, WA2CWA]

One of the most common problems is cable chafing as it winds on and off the drum as you raise and lower the antenna.  Cable chafing can also occur in the cable/pulley area if the pulleys are not rotating freely. Grease can slow the process of chafing and individual wire breakage in the cable but periodic inspection of all the cables is necessary. Weather, over time will make the grease less functional unless re-applied. In my case, the cable rot/breakage occurred well up the tower and was not easily seen from the ground level.

In the case of a crank-up/tilt-over tower, going the cheap route for materials is not a great idea. Also, climbing a two/three/four section tower requires caution since you're sticking your feet and toes between sections as you climb. When I climb my baby, all the sections are resting on the mechanical brake and there is a 4X4 shoved between all the sections further down near the base. If sections are not fully nested against something solid and one or more sections slip, even a few inches, you could lose some toes or part of your foot.

[Jim, W5JO]

Pete no one said anything about cheap.  Many hardware stores don't charge premium prices for good quality products.  Read the label and follow directions.

 I just replaced mine with locally purchased product that has strength ratings of 2K lbs and cost me about $20 less than ordering.  Aircraft parts place really get in your pocket because they must sell certified products.  That QC is unnecessary here if you buy at reputable stores.

[DMOD]

According to some tables from FortuneRope, The breaking strength of Aircraft grade 1X7 3/32" SS rope is 1,200 lbs.
  
1/8" SS wire rope is between 1,700 and 2,100 lbs, depending on stranding.

So I would say that if the weight of all the total members being lifted is less than 750 lbs, you're in good shape with 1/8" SS wire rope.

I would also recommend some Marine Grease to grease and lubricate the wire rope and all mechanisms, such as these:
http://www.schaefferoil.com/221-moly-ultra.html
or
http://www.autozone.com/autozone/accessories/Coastal-14-oz-396-893-g-premium-marine-grease?itemIdentifier=692293

Phil - AC0OB

[W2VW]

From U.S. Tower site:

QUESTION : Cable replacement and maintenance.
ANSWER : We recommend that you replace your cables every three years, with regular inspection of the cables. You need to look for any rust, broken strains and/or kinking.  We do not recommend lubricating the cables as can cause a more serious damage to them.
End paste.

Grease attracts crap and can hold moisture inside the cable making it rust from the inside out. If you really want grease there are modern varieties which repel water even when aged.


Stainless cable may not be what you want:

http://www.latticetowerspares.com/wireropeinfo.htm

[Todd, KA1KAQ]

Wow, didn't know they recommended changing it so often. TNX for posting that, Dave. Mine's been on there since I rebuilt and installed the tower back in '88-'89. Figured it would need replacing when I move it, hopefully it won't cause problems taking it down.

Seems there was some great synthetic wondergrease out there that woouldn't gum up or break down with time. Mobilith or something along those lines? Can't remember. Grease would probably be more of a help if you worked the tower a lot, otherwise sealing it up in other ways would be attractive. Of course, if you're cranking it up and down a lot, the cable is subject to more wear and tear anyhow, so it becomes more of a moot point.

Mine hasn't seen any action since the mid-90s. Had a helluva time finding it when I was up there recently, the poplar and pine trees had overtaken it.

[Jim, W5JO]

Wow, didn't know they recommended changing it so often.

Depending on service, I am not so sure.  Look at elevator cables which are inspected ,checked and greased regularly.  Same for aircraft cables.   In all my years around aircraft, I have never saw a need to replace one.
This is not to say that cables that support equipment that has a direct affect of human life may require replacement more often.

When you get the tower down, inspect the cable Todd.  If there is no rust or abrasions then it is still good.  It takes a very long time for those strands to rust through and you will be able to tell.  Get a pair of leather gloves and run the cable through your hand.  If it sticks anywhere or does not slide smoothly, then replace the cable.  If it is smooth then it will be fine.

[ke7trp]

SO Galvanized steel is the best choice?
Mine is 30 years old.  Seems solid. Only a few hairs sticking out but the cable is smooth with no rust.

What do you guys do about the Crimped fittings. I called around and was told you need a big press and dies.
 

C

[W1AEX]

There's a lot of good stuff to digest here. When I installed my last galvanized steel cable back in 2008 I was advised by a guy who does tower service NOT to apply grease to the lift cable. The reason he stated was exactly what Dave W2VW cited from the US Tower site, the grease will trap moisture inside the cable and it will rot from the inside out. There was a section of cable from the length I installed back in 1988 that was greased, and the warning seemed to hold true as that was where it rotted through. However, the cable was NOT thoroughly greased from top to bottom, so that's probably why the the greased section failed. Also, who knows if the grease I used was even suitable? A couple of big rig drivers that I know were also pretty adamant about not greasing wire rope cables as they use the same type of cable for various control functions on their trucks (emergency brakes?) and greasing them pretty much guaranteed a short life.

Dave - W2VW that Lattice Towers "wire rope information" page has tons of information. They clearly state that wire rope lift cables installed in towers SHOULD be thoroughly greased, and you need to use the good quality stuff that doesn't break down quickly. The Unirope LTD company that one of your links points to also firmly states that a galvanized cable should be well lubricated to prevent damage and pre-mature failure. So... this looks like an area that the experts can't agree on.

A closer inspection of the cable that I am replacing indicates only one small section of rot, which is in the photograph at the top of the thread. That spot was centered in the bottom pulleys in the mid-section of the tower. I would assume that over the past 3 years, moisture rolled down the cable and simply saturated that short horizontal length where it sat in the pulleys since 2008. I would imagine that if I went out once a month and moved the tower up 1 foot and locked it there, then a month later moved it down 2 feet, and then repeated that pattern each month, that it might have delayed the onset of corrosion, but who knows.

I'm guessing that with a recommendation to change out the cable every 3 years that US Tower probably uses galvanized lift cables in their products. One thing is certain, that stuff is cheap, and it's very strong. It really only takes about an hour to install a new cable, so perhaps that's the best way to go. Just mark it on the calendar so you don't forget to replace it when it's time!

Pete CWA I really like the idea of using an electric winch with a 10 foot control cord for the tilt over function. That would get you out from under the groaning, creaking monster as it goes through the tilt process and would probably keep you out of the evening news in the event that the hinge pin decided to crap out. I'll have to dig around for more information about electric winches.

Clark, thanks for the link to the online supplier. I'll look at their stuff later today.

Looks like I have a little more homework to do...

Rob W1AEX

[Pete, WA2CWA]

Pete no one said anything about cheap.  Many hardware stores don't charge premium prices for good quality products.  Read the label and follow directions.

 I just replaced mine with locally purchased product that has strength ratings of 2K lbs and cost me about $20 less than ordering.  Aircraft parts place really get in your pocket because they must sell certified products.  That QC is unnecessary here if you buy at reputable stores.

If you're happy with your purchase, that's all that counts. I've bought galvanized steel cables from the local emporiums in the past and they never seem to last. Fortunately we have an industrial wire rope fabricator/supplier within reasonable driving distance whose pricing was not out of whack with the rest of the world. For the tower application, I don't mind spending additional money if I feel comfortable with the product.

[Pete, WA2CWA]

Pete CWA I really like the idea of using an electric winch with a 10 foot control cord for the tilt over function. That would get you out from under the groaning, creaking monster as it goes through the tilt process and would probably keep you out of the evening news in the event that the hinge pin decided to crap out. I'll have to dig around for more information about electric winches.

Clark, thanks for the link to the online supplier. I'll look at their stuff later today.

Looks like I have a little more homework to do...

Rob W1AEX

I believe (from memory - I'd have to look at my EZ-Way manual) used the 7X19 type of cable. So when you buy, make sure you know what you're getting.

Since day one, I was never comfortable standing under the tower as I cranked it over. Back then I was into beam antenna experimentation so the tower was cranked over numerous times. I finally fabricated a "sort-of" tilt-over motorized winch.

I installed a steel plate at the bottom of the permanent pole mount; the part that actually is bolted into the cement; then mounted a Sears AC operated reversible motor (had to move two wires around for it to reverse so I fabricated a bracket with a DPDT switch on it); mounted a 6 inch belt pulley on the shaft; mounted a 4 inch (or 3 in) on the hand crank shaft of the winch; went to the local auto store to find an off the shelf belt that had roughly the required length and width dimensions and mounted the belt on the two pulleys. The Sears motor had a 10 foot cord and plug so I could stand safely away from the tower. With the plug in one hand and an AC extension cable in the other hand, I would energize the motor to tilt the tower slowly down;  when done, flip the DPDT in the other direction, energize the motor, and the tower will slowly raise. My biggest problem was frequent slipping of the belt on the pulley and the pull pressure on the worm drive of the winch. After 30 years of doing this, the winch bearings are definitely started to wear.

This is what we will be installing shortly. I actually bought it several years ago when it was less then $500.
http://www.grainger.com/Grainger/DAYTON-Electric-Winch-3VJ63?Pid=search
They have many more; some less money and some a lot more money:
http://www.grainger.com/Grainger/ecatalog/N-1z0r596/Ntt-motor+winch

[W2VW]

Know the differences between a winch and hoist.

Failures are not pretty.

http://www.w4abc.com/drive.html