Wire rope load limit

mattcamp · Post by **mattcamp** » Thu Jan 22, 2015 1:19 am

For the engineers out there...

I've been comparing 1/4" wire rope available from both Home Depot and Harborfreight and the load limit figures are wildly different. HD claims a load limit of 1400lbs for their 'Everbilt 1/4 in. x 100 ft. Galvanized Wire Rope', while HF claims 6160lbs for their '1/4 in. x 50 ft. Aircraft Grade Wire Rope'.

Can I trust that rating on the HF rope? They claim 'aircraft grade' but I'm not sure if that's just a marketing term or if it really justifies the vast different in load capacity.

Post by **Sham** » Thu Jan 22, 2015 3:09 am

I find that anything from Harbor Freight should be looked at with skepticism. It all seems made to be inexpensive, not for quality.

FlyingMonkey · Post by **FlyingMonkey** » Thu Jan 22, 2015 7:11 am

Sham wrote:I find that anything from Harbor Freight should be looked at with skepticism. It all seems made to be inexpensive, not for quality.

I have to agree with you there. It's always a crap shoot with HF purchases. I love my HF metal band saw & it's cut a whole hell of a lot of steel for me, but some of the blades I have bought there have broken on the first cut while other "brand name" blades have never done this. Things like caster wheels & hardware are just as good as you will probably find at HD or elsewhere, but if I had to rely on something for safety reasons & would either over engineer it or spend more elsewhere.

I guess if your application is no where near approaching the failure limit then go cheap but why risk it if this is a safety concern. Especially if it is the safety of people around you.

LionsNzebras · Post by **LionsNzebras** » Thu Jan 22, 2015 8:05 am

You did not say what your application of the wire was for. But this might work for you.

Try looking at mule tape, it comes in several strengths, is cheep too.
http://www.ebay.com/bhp/mule-tape

watchyourfeet · Post by **watchyourfeet** » Thu Jan 22, 2015 8:09 am

LionsNzebras wrote:You did not say what your application of the wire was for. But this might work for you.

Try looking at mule tape, it comes in several strengths, is cheep too.
http://www.ebay.com/bhp/mule-tape

I never thought of using mule tape for my structure. Do you have any experience of it? Can you speak to how much it stretches under load? I have been looking for an option for a tensile structure that needs as little stretch as possible.

mattcamp · Post by **mattcamp** » Thu Jan 22, 2015 8:11 am

FlyingMonkey wrote: I guess if your application is no where near approaching the failure limit then go cheap but why risk it if this is a safety concern. Especially if it is the safety of people around you.

Yeah, totally agree.

For this reason I'm likely going to use high-grade ratchet straps as they have a higher working-load limit and also makes tensioning much easier... but I was curious about the weird numbers on the wire rope.

FlyingMonkey · Post by **FlyingMonkey** » Thu Jan 22, 2015 8:15 am

LionsNzebras wrote:You did not say what your application of the wire was for. But this might work for you.

Try looking at mule tape, it comes in several strengths, is cheep too.
http://www.ebay.com/bhp/mule-tape

Mule tape totally rocks & has so many uses. Back when I used to pull cable we always ended up with "scrap" mule tape that would usually end up in the dumpster if I didn't find it first.

FIGJAM · Post by **FIGJAM** » Thu Jan 22, 2015 8:27 am

Mule tape has very little, if any, stretch to it.

I have some 1" wide that is rated at 2500 pounds.

Got about 300' for free.

FlyingMonkey · Post by **FlyingMonkey** » Thu Jan 22, 2015 8:47 am

FIGJAM wrote:Mule tape has very little, if any, stretch to it.

I have some 1" wide that is rated at 2500 pounds.

Got about 300' for free.

Nope. No stretch at all. So for an application that needs to absorb energy (say a >70 MPH wind load) it may not be a good choice. But for general use (and bondage) it's great & as you know not hard to get for free.

ygmir · Post by **ygmir** » Thu Jan 22, 2015 9:10 am

well, I'd only say not even H F should be dumb enough to sell a cable that won't hold well over rated strength. That said, I'd only trust it to the rating. Good quality cable will hold much more than rated before failing. A lot has to do with material and stranding, in wire rope.

if you want no stretch, maybe consider chain? infinitely adjustable, and with the threaded adjusters, easy to tighten.

SnowBlind · Post by **SnowBlind** » Thu Jan 22, 2015 12:01 pm

I like the idea of mule tape. How do you guys attach it? Knots? Or any other technique?

LionsNzebras · Post by **LionsNzebras** » Thu Jan 22, 2015 6:29 pm

With mule tape its very strong, and should handle the wind with no issue, even in a bouncing situation. I have pulled some serious cable with that stuff.

The 2500 stuff is great, but you can also get it higher rated, the cost goes up as the rating goes up, if you go on ebay you will find tons of it, usually the printing on the stuff failed so they flog it off cheep, the tape itself is still good.
Even used stuff is usually very good, as long as the tape itself is not damaged in anyway.

Wire will corrode in the alkali dust, you may get 1-2 years out of it, but would not trust it for its load rating after that. Anyone else have thoughts on this?

You know the tear dropped shape metal piece you can buy to build loops with your wire? Sorry I forget what they are called, but you can use this for the mule tape then use a weight rated carabiner to clip (honestly I think the carabiner will be your highest cost on that part) You may also be able to find some parts at the hardware store that will help you. If not use ratchet straps!
I am unsure if the carabiner weight capacity will meet your requirements though, for the 70mph winds.

When in doubt, over engineer it.

watchyourfeet · Post by **watchyourfeet** » Fri Jan 23, 2015 8:14 am

LionsNzebras wrote: I am unsure if the carabiner weight capacity will meet your requirements though, for the 70mph winds.

When in doubt, over engineer it.

Most climbing-rated (UIAA) carabiners are rated to 22-25 kN along their major access, or about 5000 lb, which will be plenty for almost any application. If you search around the web you will find them for about $5 each, sometimes less. Better yet would be if you have a climber friend who has some old ones lying around that they aren't using anymore.

LionsNzebras · Post by **LionsNzebras** » Fri Jan 23, 2015 8:48 am

watchyourfeet wrote:
LionsNzebras wrote: I am unsure if the carabiner weight capacity will meet your requirements though, for the 70mph winds.

When in doubt, over engineer it.

Most climbing-rated (UIAA) carabiners are rated to 22-25 kN along their major access, or about 5000 lb, which will be plenty for almost any application. If you search around the web you will find them for about $5 each, sometimes less. Better yet would be if you have a climber friend who has some old ones lying around that they aren't using anymore.

I did not know this, thank you very much.

watchyourfeet · Post by **watchyourfeet** » Fri Jan 23, 2015 9:18 am

LionsNzebras wrote:
watchyourfeet wrote:
LionsNzebras wrote: I am unsure if the carabiner weight capacity will meet your requirements though, for the 70mph winds.

When in doubt, over engineer it.

Most climbing-rated (UIAA) carabiners are rated to 22-25 kN along their major access, or about 5000 lb, which will be plenty for almost any application. If you search around the web you will find them for about $5 each, sometimes less. Better yet would be if you have a climber friend who has some old ones lying around that they aren't using anymore.
I did not know this, thank you very much.

Happy to be of service

^Rhino! · Post by **^Rhino!** » Fri Jan 23, 2015 9:44 am

They have some links that are shaped like a standard carabiner at Home Depot, except that they're oval and made for attaching two lengths of logging chain together, and rate at over 5000 pounds. I use a pair of them to attach trailer chains to the bumper of my truck as a safety precaution (in case the trailer neck pops off the hitch) and they are superb for this. Costs about $3-5 each. The gate screws shut instead of being a snap link arrangement for added security, and you could even use a crescent wrench to tighten it up really tight.

FIGJAM · Post by **FIGJAM** » Fri Jan 23, 2015 10:56 am

I use those and thought they were called "Fix-a-Links".

motskyroonmatick · Post by **motskyroonmatick** » Fri Jan 23, 2015 12:55 pm

Rigging- Cable, Chain and Straps aren't really that expensive for the work done with them and rigging shops can professionally install end treatments and provide hardware for tensioning and a myriad of other things.

^Rhino! · Post by **^Rhino!** » Fri Jan 23, 2015 1:27 pm

FIGJAM wrote:I use those and thought they were called "Fix-a-Links".

Them's the ones.

EspressoDude · Post by **EspressoDude** » Mon Jan 26, 2015 6:17 pm

the bigger number for HF cable is the breaking strength at 6160 pounds. Other similar is rated 7000 pound breaking strength

with a safety factor of 5 to 1; 7000 pound breaking strength is 1400 pound working load, same as HD cable.

So HF has a bigger number than HD, but is a DIFFERENT NUMBER.

Read up on steel cable

silas thatcher · Post by **silas thatcher** » Tue Jan 27, 2015 11:25 am

gonna throw my experience with wire rope in here --- used to use it as a clothes line.... strong, held up well, got some used lengths left over from work... i used (crap can't remember the name off the top of my head ) wire rope clamps to secure the ends... long story short,with all the kids hanging on it while playing, one end broke loose and whipped around to catch one son in the face narrowly missing his eye...cuts, scratches and bruises had me take it down and replace it with rope...i'd rather get hit with rope than wire rope...

in short, if anything at all happens to your structure, there may be lengths of wire rope whipping around with no discrimination between flesh and objects... if something snaps loose, i'd rather suffer the temporary sting of mule tape than the frayed end of broken wire rope any day...

i've used mule tape at work ( electrician ) and that stuff will take some punishment... i've seen it in 1500 and 2500 pound ratings... the 1500 i think is about 3/8" wide and the 2500 is about 1/2" wide... i really don't think that too many situations on the playa will duplicate the strain on the mule tape that i have seen on the job... it is slick and will not hold a simple knot real well... i like the bowline for knots and a trucker's hitch for tightening...

maladroit · Post by **maladroit** » Tue Jan 27, 2015 5:04 pm

silas thatcher wrote:gonna throw my experience with wire rope in here --- used to use it as a clothes line.... strong, held up well, got some used lengths left over from work... i used (crap can't remember the name off the top of my head ) wire rope clamps to secure the ends... long story short,with all the kids hanging on it while playing, one end broke loose and whipped around to catch one son in the face narrowly missing his eye...cuts, scratches and bruises had me take it down and replace it with rope...i'd rather get hit with rope than wire rope...

in short, if anything at all happens to your structure, there may be lengths of wire rope whipping around with no discrimination between flesh and objects... if something snaps loose, i'd rather suffer the temporary sting of mule tape than the frayed end of broken wire rope any day...

A taut rope with a load in the middle will be experiencing tension many times greater than the load. 200 pounds in the center could result in 1500 pounds of force applied to the anchor points.

Post by **mdmf007** » Tue Jan 27, 2015 6:09 pm

ouch - There is a lot of energy in a tensioned line, be careful and plan on it parting. Think redundancy and what ifs - it helps to overbuild.
Most wire rope will have a certificate on the end of the spool (or did when manufactured) take a look if buying bulk.

Wire rope load limit

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