I had a peice of flat webbing fail on me a little while ago, and my search for a how lead to soem other questions.

The vendor advertises the slaing at 5000lbs, but they only have a two inch boxed-x stitch. everyone we went and talked to ( we had similar products made buy two different companies) emphaticly stated that these products would not be fit for anything but a chainsaw lanyard.

It seems that we need some more detail inthe standards to get consistancy in these poducts. Or is there a standard for lifting slings that we can apply to our usage.

One vendor swore up and down that that is a ligitamate rating for the product, and that they send them out to be broken. Don Blair stated that they may hold to a single slow pull of 5000lbs but are not fit for any shock loading or have enough stitching to stand up to regular use.

Any thoughts?

Reply to post by JPS, on November 18, 2000 at 23:20:28:

I agree with Don. For a static load, it may be OK, but after a few slam dunks, the stitching is likely to break.The box stitch is the weakest way to make a loop. I think you would be better using a Beer Knot or Water Knot than rely on the box. Check out the section in On Rope about stitching.

Bar tacks are more accepted stitching patterns.

Buy slings from companies that make gear for mountaineering. They have more rigorous testing and certification standards. The box sewn slings that I have seen look like they are home made. When I see poor stitching I am suspicious of poor webbing. When I look at a chipper and see poor welds or a poor paint job, I am suspicious of the whole machine. I take these things as indicators of the whole design process.

Where did the sling fail? Stitching or webbing? Shock load or static?

When I am lifting heavy loads with slings I put the stitching opposite the girth hitch rather than in the loop. I think that takes some of the load off the stitching since there is friction on the webbing. Any thoughts?

Tom

Reply to post by Tom Dunlap, on November 18, 2000 at 23:20:28:

Hi Tom, Nice meeting you finaly at the TCI.

The failure came in the fabric, not the stitching. The question about that came up while seeking an expaination for the failure.

About a 125lbs log sling girth-hiched, 'biner tied to rope, 'biner for a fales-crotch, then down to a port-a-wrap. wood swung out smoothlly, then fell to the ground (driveway, past target I intended to clear. whew!. Sling was broke with meling. SOme looking like from stress of seperation, but I could not figgure what started it.

I asked opinions from several people in the MKE area, and had Lance Wallace do some more. All I could get was a few people insisting I had to have let the rope run trough it.

Anyways; I asked around in NC too and finaly Ken Johnson posited that there was a slight slack in one side that sawed into the other, wich allowed failure. It was only the fourth or fifth use of that sling.

After that I stopped using webing and had Lance splice some eye-and-eyes out of hardlay.

Another of Don's concerns is abraision of the stitching, how much rubbing will they take if you pout them against the wood?

Reply to post by jps, on November 25, 2000 at 10:18:41:

About the broken sling: A bar-tacked sling's strongest point is in the stitch. The stitch is actually stronger than the sling material itself. I read this story and had to reply, being familiar with the gear. Spectra slings (usually small,though) would probably be better, since they have a higher breaking strength than nylon and a much higher melting point (can't burn it with a lighter. 5.5mm spectra cord had a breaking strength of 5500lbs. and is super durable. I think that doubled (two slings for safety)would be pretty much bomb-proof. (Spectra cord needs to be tied with a triple-fisherman's knot to create a sling!!!)

Reply to post by JPS, on November 18, 2000 at 23:20:28:

The advice given to you is absolutely correct, a box stitch is completely inadequate. Bar-tacking is absolutely the only way to go (@ least 5 bars seems to be standard). Also, I am curious, was the webbing actually flat, or tubular? 1" or 2"? 2" flat (nylon) I think has a breaking strength of around 5000lbs., and 1" tubular has the same strength. 2" tubular has a strength of near 10,000 or more lbs. (Don't quote me on these numbers, but I know that they are fairly accurate!)

Reply to post by Chris Rose, on November 25, 2000 at 20:15:21:

Ken is on the right track I think. If you saw some melting it is probably from where the sling choked onto itself. Kind of like a small rug burn.

I have been using a selection of tubular webbing slings for several years with no problem. They get used for limb wood and I try to not slam dunk onto them. The retirement criteria are the same as for rope. Burrs, tears, burns.

Spectra slings are nice. That is what my daisy chain for SRT is made from. If you are going to use spectra, buy them sewn/bar tacked from the factory.

There is a wide range of material quality for tubular webbing. I have seen box stitched slings at vendors too. I have always been suspicious of them.

When I have climbing ropes that have life in them but are not trashed I will make up slings. Tie a double fisherman's knot and melt the ends. Woek through the numbers so that you still end up with a high enough safety factor. These rope slings don't come into play when it is time for slam dunk or heavy loads. Just another way to "Get the oink out of the pig!" When the slings are retired from rigging we use them to drag logs with the ATV.

Tom

Reply to post by Chris Rose, on November 18, 2000 at 23:20:28:

I think it's 1 in flat nylon.

I pulled the catlog and they give it a safe working strength of 1200lbs!

It is listed for use as a lowering choker! and they have them in ntheir speedline kit too!

I wonder, would they pay if someone put put a half ton chunk through a roof?

Reply to post by JPS, on November 26, 2000 at 15:42:50:

Wow! That really surprises me and at the same time, it's actually scary. I guess education is the key. I don't want to instigate anything but if this (inexpensive) product is being sold for a purpose which it is not suited for, something should be done before somebody is needlessly hurt.

Reply to post by Chris Rose, on November 27, 2000 at 17:51:55:

Wich brings me back to the question;
is there a standard for lifting slings that we can apply to our usage?