# Pull Test--Ice Tail Splice



## moray (Jun 18, 2009)

I have been using Samson Ice Tail for my hitch cord for the last couple of years. Among its excellent features are high strength, heat resistance, ease of splicing, pliability, and good surface friction. It's also relatively cheap. I like a lot of room between my belt and my friction hitch, so my split tail measures about 50 inches between the eyes. This has proved to be a little too long for some of my friends I occasionally take climbing, so I decided to make another shorter one.

The first thing I discovered when I dusted off Samson's splicing instructions for Ice Tail is that my old one is substandard in terms of bury length. Not to worry, both splices were backed up with locking Brummels and plenty of stitching. Now I like to follow the manufacturers's instructions when I can, but I absolutely required that the friction knot be entirely outside the splice zone, meaning each splice's bury had to terminate well short of the friction knot. I was quite sure much of the excellent performance of this cord came from the fact it was (1) extremely pliable and (2) only 5/16 in in diameter.

If I was going to do another substandard bury, a test was called for.

My intention was to put a halfway decent eye with stitching at one end of a 7-ft. piece of Ice Tail, and put a grossly substandard eye at the other end with no stitching. I would measure the force needed to pull the bad eye apart, then replace it with a fresh eye with a bury 2 inches longer. Pull that one to failure, measure the force, then repeat again with a still longer bury. I should end up with a nice little chart of numbers that should provide useful guidance for making the real split tail for field use.

I was in for a surprise.


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## moray (Jun 18, 2009)

Thanks to an excellent suggestion from pdqdl about a year ago, I have put together a hydraulic rig that can apply forces up to 10,000 lbs. and measure them with 2-lb. resolution over the whole range from 0 to 10,000. Accuracy over the full scale is on the order of +- 10 lbs.--far, far better than I need.

For the first test splice I decided to use a bury of 4 inches, 2 of which was tapered. This is only 20% of Samson's spec, so it should be easy to pull apart.

The first picture shows the load cell with light tension on the test rope.







The second photo shows the actual splice. The distance between the arrows is 4 inches, and the righthand arrow points to the throat of the eye where the bury begins (unfortunately the camera is in the plane of the eye so the eye isn't visible).






The last photo shows the anchor for the eye under test. The screw link is there to provide a strong subsitute for a carbiner.


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## moray (Jun 18, 2009)

I actually did two pulls on this first setup. On the first pull I reached 2052 lbs. and then released the tension. As this was the first pull with my new rig, and I had expected an easy pull, I had not provided any safety features for recoil. Over the next hour or so I remedied the safety situation and resumed the test. I pumped steadily on the hand pump, adding about 1000 lbs. every 5 seconds. After the gauge reached about 9800 lbs., the next pump stroke took the read-out out of limits, and the stroke after that broke the rope. Quite a maiden voyage for my new rig!

The results are shown in the photo.






The arrow points to the substandard splice, which is still intact. The circle indicates the two legs of the test eye, which extend beyond the photo. As you can see, a couple of strands in the main rope actually survived the torture.

When I make that new tail, I'll probably bury 10 or 12 inches and stitch it well. I will have 100% confidence that it will do its job and still provide a huge safety margin. (Do I need to put in a disclaimer--I am not recommending anything to anyone else?) 

I am left wondering, though, why Samson doesn't provide less restrictive instructions for the Ice Tail splice. They know what the rope is for (they do call it Ice *Tail*), and they must know that stuffing the whole thing with buried core makes it fat and stiff and much less useful. They also must know you don't need 20 inches of bury for the splice to hold. I am guessing Ice Tail is a very minor money maker for them, and they have little inclination or motive to improve the one-size-fits-all hyper-conservative splicing instructions they have published.


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## Blakesmaster (Jun 18, 2009)

THIS is interesting stuff. How did you build your testing rig? Have you tested other types of rope/splices. How are you certain the amount of pressure being appied on each test? Man, this is beautiful ####, I want to know more.


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## masiman (Jun 18, 2009)

moray said:


> .....I am left wondering, though, why Samson doesn't provide less restrictive instructions for the Ice Tail splice. They know what the rope is for (they do call it Ice *Tail*), and they must know that stuffing the whole thing with buried core makes it fat and stiff and much less useful. They also must know you don't need 20 inches of bury for the splice to hold. I am guessing Ice Tail is a very minor money maker for them, and they have little inclination or motive to improve the one-size-fits-all hyper-conservative splicing instructions they have published.



I wonder how the splice performs over time, i.e. cycle testing, element exposure, gradual abrasions, etc.


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## canopyboy (Jun 19, 2009)

Great test, I was thinking to test my bee line splice with locking brummel and 6" bury the same way. What kind of load cell did you use? We calibrated dynamometry all the time at my old job, and I had come up with a similar set up for high load cals that I wanted to use for testing splices.

Sure makes you feel better about what you're climbing on, doesn't it?


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## moray (Jun 19, 2009)

It's good to see this has generated a bit of interest!


Blakesmaster said:


> ...How did you build your testing rig? Have you tested other types of rope/splices. How are you certain the amount of pressure being appied on each test?...


This was my first pull. I have a long list of experiments I want to do now that the basic rig has proved out. 

The load cell is connected to an electronic display that converts the load-cell voltage to a reading in pounds. Load cells are very linear devices, so if it is accurate over some part of its rated range, it is probably accurate over the whole range. I have tested mine with known weights from 2 lbs up to 158 lbs, and it has been dead on every time.
My rig is still very much a work in progress, but I can tell you one of the toughest challenges is finding a suitable frame to anchor to. I am using part of a butternut tree I took down a couple of weeks ago. It is not ideal, but it is free. Loops of chain at each end of the frame provide adjustable, non-stretchy anchors. The tree itself is too big to flex much even under a load of 10,000 lbs. The big problem facing me is how to prevent a recoiling rope from whacking something I care about, like the load cell. The operator (me) is well off to the side at the end of a 7-foot hydraulic hose.



masiman said:


> I wonder how the splice performs over time, i.e. cycle testing, element exposure, gradual abrasions, etc.


What I have read, and this is consistent with my own informal observations, is that splices become very stable after a few load cycles, as if the core and cover become more or less physically locked together. If the throat is properly stitched, the splice cannot creep apart.



TreeCo said:


> ...How does Ice Tail hold a scaffold hitch?...


I tied one just now to see... Ice has a very soft hand--it is noticeably softer and more pliable than the polyester in Tenex. It is also not as slippery as Tenex. I would think all those features together would make it shine at holding knots, but I never knot it myself.



canopyboy said:


> ...What kind of load cell did you use?...Sure makes you feel better about what you're climbing on, doesn't it?


The load cell was made in (where else?) China. I love your line about feeling better! A lot of people seem to have an incurable distrust of splices, but here is the cure, and it doesn't require a load cell: make a simple eye in some Samson Tenex, then try to pull it apart with your truck. Nothing like a little hands-on experience to change your thinking and dissipate your fears.


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## pdqdl (Jun 19, 2009)

If you want to control the risk of flying components, load the rope or other dynamic elements with non-dynamic weight. Regardless of the force involved with breaking the rope, at separation you may have a lot of velocity, but not much momentum.

Throw some fabric over the stretched parts, like an old horse blanket, gunny sacks, or some other material of low value and sufficient soft weight to do the job. If necessary, you could add weight by wetting the fabric. [great idea: test a wet splice, and see how it performs] 

The momentum of parts flying off to either side of the pull is rapidly absorbed by trying to move the extra weight of the fabric. Quick and easy fix.

By the way, I love reading your test reports. Keep up the good work.

I have a suggestion for getting more use out of your load cell: Rig your hydraulic cylinder to a pulley system attached to the load cell, then load the splice with the full force. I would suggest using two doubled pulleys for a 5:1 power gain. Using mechanical advantage to reduce the pull on the load cell and keep the force higher against the splice should give you more power to break splices and less risk of breaking the stuff you want to protect. By attaching the load cell to a line at the end of a pulley, you might also remove the load cell from the danger zone of flying parts.


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## pdqdl (Jun 19, 2009)

*Needs more information!*

I can't tell from the pictures where the rope broke.

At a splice, near a splice, in the middle? Some point of deflection or bending?


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## canopyboy (Jun 19, 2009)

pdqdl said:


> I have a suggestion for getting more use out of your load cell: Rig your hydraulic cylinder to a pulley system attached to the load cell, then load the splice with the full force. I would suggest using two doubled pulleys for a 5:1 power gain. Using mechanical advantage to reduce the pull on the load cell and keep the force higher against the splice should give you more power to break splices and less risk of breaking the stuff you want to protect. By attaching the load cell to a line at the end of a pulley, you might also remove the load cell from the danger zone of flying parts.



Unless you're maxing out your load system, you don't want to do this if you can help it. Doing precision force and moment testing for the Navy has given me some insight into this type of thing. Pulleys aren't perfect. Highly loaded pulleys are even less perfect. Your readings will start to suffer in accuracy with every pulley between your load cell and what you're measuring. In some of our systems we found up to 10% deviation (actually about 10% for the first pulley, then 7% for the second, etc....) for each pulley we put into the system, and they were high quality ball bearing pulleys. Not that extreme accuracy is needed for this, but if you don't need the mechanical advantage to protect the load cell from being over-stressed, you might as well leave it attached directly in line with the splice.


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## 046 (Jun 19, 2009)

moray... nice job!!

have always put a disproportional amount of weight to what few pull tests that's available. 

this raises my confidence level for splices. traditionally have never trusted splices. much rather depend on a knot I personally tied vs a splice done by no telling who.


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## pdqdl (Jun 20, 2009)

Well of course there will be frictional losses and changes from ideal using any mechanical advantage.

But if your system is designed to deliver 10k, and you max it out on the preliminary test, you need to invent another way to measure. 

Since the Icetail rope is not rated for anywhere near that great a load, I suspect that Moray's equipment needs to be calibrated a bit better. What really matters, though, is the relative results he will get from splice buries of different lengths.

If you don't like pulleys, Moray, you could also rig a lever mechanism that would do the same job. Unfortunately, there are not many levers you can hit with 10,000 lbs of hydraulic force that will still do the job. By the time you rig that up, you will spend a fortune on metal.


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## moray (Jun 20, 2009)

Good discussion of the very issues I have been wrestling with. 

The rope broke right at the end of the short bury. 

Mechanical advantage: I'm with canopyboy on this one. Besides the accuracy issue, you have the problem of acquiring a 10-ton or higher SWL block, extra heavy duty anchors, an extra heavy duty frame, etc. But worst of all, as I am now beginning to see, you now have big chunks of metal (the block) that want to fly. The sweet spot, for me, was 10K lb. This allows me to test any climbing rope to failure. Of course I am not interested in breaking ropes, per se, but in teasing out some of the principles governing the behavior of knots and splices.

I did a couple more tests today which I will report in a new thread, but I can tell you the recoil problem is quite serious. I purposely designed my system so the parts would have as little stretch in them as possible. If something doesn't stretch, it can't store energy and can't recoil. The longer and stretchier the rope under test, the more energy available for recoil. The Icetail was relatively short, maybe 3.5 feet, and very non-stretchy. What's more, it snubbed itself off because two strands remained intact.

I really saw some recoil today when breaking a piece of 5/16 inch Tenex. It was only about 30 inches long, and broke near the middle. The end connected to the hydraulic cylinder and load cell sent them flying about 2 feet in spite of an inadequate snubbing system I had in place. I am leaning towards a positive snubbing system in which a rope, as strong as the one under test, is connected in parallel with the test rope. Before anything can fly more than a couple of inches, the snubber goes taut and then stretches to absorb the kinetic energy of the recoil. As I say, this is still a work in progress.


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## pdqdl (Jun 20, 2009)

Try the blankets. It works, even for chunks of metal. 

The more weight, the more mass you will need to absorb the flying chunks.


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## moray (Jun 20, 2009)

Pdqdl, I didn't mean to ignore you; I have been thinking about using some old rug that I have. A rug (or blanket) folded over the experiment should confine the recoil, one would think. But I don't think it would absorb much of the momentum. The wadded-up recoiling rope would whack the nearest clevis like a 2-or-3 hundred MPH baseball without its cover. The clevis pushes the load cell. Whack! The load cell pushes the cylinder. Whack! It's those Whacks I want to minimize. I can help myself a lot by moving the load cell to the other end of the cylinder, and I think I am going to have to do that.

BTW, I am inclined to believe the 10,000 lbs from yesterday, even though I certainly have done no calibrating at that end of the scale. The clean 5/16 inch Tenex I broke today measured 4400 lbs, slightly below spec. Could a sample of Icetail actually be 17% or 18% stronger than the published average? Would that be merely unusual, or unbelievable? In any event, I will stay alert for the chance to weigh a truck or some other large known weight.


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## pdqdl (Jun 20, 2009)

Try the blanket, let me know how it does.

What thickness Icetail were you breaking? I thought you were doing smaller stuff used for eye-to-eye prussics. That doesn't come in anywhere close to 10k.


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## moray (Jun 21, 2009)

Is there more than one size? Mine is the 5/16 in, 8500 lb, stuff meant for prusiks. 80% technora, 20% polyester. I will try the blanket.


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## moray (Jun 22, 2009)

*wet blanket*

I tried the blanket today--actually a peice of rug. The rug was about 5 ft by 3 ft, more than enough to entirely cover the experiment. When the rope broke at 4460 lbs, the recoil still caused the cylinder and attached load cell to jump back a foot or more. If the rug did anything useful, it wasn't apparent.

I then implemented a rope snubber made from 7/16 stable braid. Once the experiment was tensioned to 500 lbs or so, I adjusted the rope so there was about 4 in of slack. There was still slack when the test piece broke, but the snubber clearly did a good job of absorbing the recoil, and the big hardware didn't move more than 2 or 3 inches.


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## pdqdl (Jun 22, 2009)

I am a bit confused. The rope breaking might slap into the cylinder, but it won't have enough momentum to move the hydraulic cylinder.

I suspect that where your cylinder is anchored has more elasticity than you are giving it credit for. If the cylinder is moving, what is it attached too?
(some pictures of the whole rig would be nice!)

My suggestion for the blanket was to control frayed rope and small flying metal attachments, not the entire hydraulic cylinder. If the cylinder is attached with a long chain or cable, see if you can shorten that attachment in some way, then extend the other end longer. Any long stretch of material will have some stretch, which will rebound. The longer the run, the more re-bound you will have. 
_(But of course, with your understanding of physics, you will know that. I'm just thinking maybe that didn't cross your mind)_ 

An alternative method might be to pre-tension the chain holding the cylinder back in the direction that the splice is being loaded with a second chain. When the rope fails, the cylinder is still under tension and goes nowhere.

By the way: if the rug was actually some really stiff old carpet, that wouldn't have worked to well. You need a flexible fabric that conforms to the rope (or other moving objects) so that the momentum is absorbed and transferred into the fibers of the fabric.

It sounds like your rope snubber is largely doing what I suggested.


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## moray (Jun 22, 2009)

My bad, I think all your criticisms apply to me. 
(1) The rug was quite stiff.
(2) There are 21 feet between anchors, so a lot of chain is available to stretch.
(3) Under tension, the cylinder is about 3 inches above the little table it sits on, and its chain anchor is about 8 inches off the dirt. When the test rope breaks, even if there were no recoil in the test rope at all, the cylinder has to fall 3 inches and the sagging chain will drag it back toward the anchor.

So I can't actually tell how much of the movement is due to rope recoil.

I like your pretension idea. If I can somehow pretension with some rope attached to the same clevises as the experiment, that will make for an improved snubber. I should probably stop letting the cylinder fall on the table by putting something thick and soft under it. The whole arrangement is embarrassingly primitive at this point! When it finally looks pretty, I'll post a picture.


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## pdqdl (Jun 23, 2009)

Here is an idea: put your load cell on the chained side of the hydraulic cylinder (instead of the spliced side). Pre-tension the whole rig to a measured amount of tension, then subtract the initial tension from the breaking tension. When you break the test rope, you may wish to compare the load on the pre-tension line just to compare for changes.

This might produce some strange results, or it might stabilize the rig for repeated tests.

Does your load cell just produce a single number that you must read, or could you plot a graph of its numbers as the rope breaks? It would be really interesting to see a chart of force vs. time on the rope breaking.


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## moray (Jun 24, 2009)

OK, for the last set of tests I did move the load cell. The components are in this order: chain, load cell, cylinder, experiment, chain. The load cell is now out of harm's way.

The load cell has an LED readout that I watch as I pump up the pressure. It also has a peak hold feature so that it continues to show the highest reading until you reset it. This is very handy for my purposes.

If I were to try to add some sort of data logging feature, I would want to see force vs. distance, but then I would need to simultaneously accurately measure distance. Why force vs. time?


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## pdqdl (Jun 24, 2009)

1. If you were plugged into a computer, it would be easy. The computer would already be logging the time.

2. It would reveal how long it takes for the rope to tear in half. "POP!", "RIP!" or "T E A R R R !" ?

I imagine that the rope (on such a non-dynamic load) would begin to tear, and the rope would consequently lengthen as part of the fibers begin stretch out of alignment, having been broken. This "lengthen during failure" of the rope might be great enough to match the stretch on your pulling system. If that occurred, I would hope to see a down-sloping graph as the rope lengthens and the load applied by the cylinder is reduced.

I guess you can just tell us, too. Which is the right word for how the rope breaks: "POP!", "RIP!" or "T E A R" ?


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## pdqdl (Jun 24, 2009)

It occurred to me that distance is pretty easy too. Graduate (mark with calibrations) your cylinder with some indelible marker. Record distance vs force, and you will probably get a parabola, essentially plotting elongation of the rope.
(this assumes no air bubbles in your hydraulic system that will expand after the rope breaks)

That would be cool too.


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## moray (Jun 24, 2009)

I think there is no question that the force vs. time curve, or for that matter, the force vs. distance curve will be a sharp sawtooth pattern. Each time the pump handle reaches bottom the rope will begin to relax and the tension will begin to drop. If I turn off the peak hold feature I will be able to watch the rope relax after each pressure pulse. I'll report back what I see.

I must say, even though it reflects poorly on my capacity for curiosity, this doesn't interest me a whole lot. The overall tension vs. distance curve (the stress/strain curve) DOES interest me, but I have to accurately measure distance or I can't get at it. Using a video camera and some sort of sliding tape measure might handle it if the camera could also see the tension readout. It wouldn't be hard to hand-plot the values and get a pretty good curve...


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## moray (Jun 25, 2009)

*Snubbing*

Here's a picture from a test I did today.







The snubber rope, 3/8 in. Stable Braid, is wrapped around the test rope about 3 times. All the slack is in the other leg of the snubber, near the ground in the background. When the test piece breaks, the snubber quickly goes taut and the recoiling test piece is forced into a tight spiral as it flies toward the anchoring clevis off to the right. This has proved to be very effective: the recoiling rope is totally captured by the spiral snubber, and the snubber stops all the hardware from moving more than a couple of inches. 

Right now I have to guess how much slack to leave in the snubber. I need a convenient way to feed slack to the snubber right up to the moment of breakage.


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## pdqdl (Jun 25, 2009)

If your force is backing off between pump strokes, you have an internal leak in either your cylinder or your pump. The check valves in most pumps are pretty reliable; I would bet on the seals inside the cylinder. 

Does the pressure bleed off completely (given enough time), or just drop some and then stop ?


Pretty good idea wrapping the rope around the test rope. Better visibility than a blanket.

I would just keep the snubber rope twisted around the test rope, go around the base of the tree and secure the tail with a rubber bungee. If you really wanted to control the length, you could tie off the tail to limit the total travel.

Kinda like a skilled groundman letting the rope run before stopping it.

So do those splices pop!, rip!, or t_e_a__r ?


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## pdqdl (Jun 25, 2009)

I think you should take more pride in your handiwork. Show us some pics of the whole setup. Stretched between two trees is fine with me. If anybody gets smart about it, we can suggest they show us a better way, with testing their own splices and establishing their own test procedures included.


Homespun methods are fine by me: they used to call that Yankee Engineering. (there are other less auspicious terms in use also)


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## moray (Jun 25, 2009)

pdqdl said:


> If your force is backing off between pump strokes, you have an internal leak in either your cylinder or your pump.



No, the rope is relaxing. I could try pulling just the chain and show that the effect is greatly reduced.



pdqdl said:


> So do those splices pop!, rip!, or t_e_a__r ?



None of the above. They BANG!


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## moray (Aug 30, 2009)

moray said:


> ...I pumped steadily on the hand pump, adding about 1000 lbs. every 5 seconds. After the gauge reached about 9800 lbs., the next pump stroke took the *read-out out of limits*, and the stroke after that broke the rope. Quite a maiden voyage for my new rig!



I believed all this when I reported it, but after nearly two months and many more tests, I am sure some of this is wrong. Here's the correction.

The actual maximum force is what the gauge actually said at the end--8000 lbs. I was reading the LED gauge in bright sunlight, and it was very hard to see. The 8000 lbs, after the break, was read by shading the gauge with a shirt. The runup to the final break is the part I should have left out. When I thought the gauge was going through 9800 lbs, it was certainly actually 7800 lbs. There was no out-of-limit condition, just an out-of-limit imagination.

Having since broken a few items in the 6000- to 8000-lb range, I am quite certain that even with my full weight on the pump handle I could not have achieved 9800 lbs. I would have had to change gears on the pump.

The actual point of the experiment remains entirely valid--the short splice held and the rope broke. I regret posting inaccurate information without also mentioning, at the time, that I had my own doubts about it. The doubt is now gone--it was wrong.


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## pdqdl (Aug 31, 2009)

Nothing makes me like a fellow better than when he owns up to a mistake. Once again, you demonstrate that you are in the upper echelon of folks to admire.

Besides, I don't really care too much for someone that is perfect, and folks that try hide their faults are only fooling themselves.


Regarding Icetail: how hard is it to cut?

The Beeline I have been using is really p###ing me off. I can't cut it smoothly with ANYTHING. Freshly sharpened knife: it dulls in one cut. Box knife with new blade: Same story. Scissors: by the time you gnaw through a few strands, you have created a giant frayed mess. Sears razor & anvil cutters: nope - it won't squeeze hard enough.

I think a good sharp chisel and hammer pounding on some really firm material might do a good job of cutting this stuff.


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## moray (Aug 31, 2009)

Thanks for being easy on me, pdqdl. Your original misgivings were entirely justified.

Ice Tail is a ##### to cut. My best scissors can't deal with it. I either hold a strand or two in one hand and use my freshly sharpened pocket knife in the other, or I hold the rope down against a cutting board and use the knife against that. Amsteel Blue behaves the same way.


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## 046 (Aug 31, 2009)

how's about a picture of entire setup... would mind being able to duplicate your set-up. being able to pull to destruction produces very useful info indeed...


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## outofmytree (Aug 31, 2009)

Sharp knife on a log is fine for beeline guys. Icetail I have no idea. Frankly I want my prussik cord to be hard to cut!


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## Ghillie (Aug 31, 2009)

Electrical tape to keep it from fraying and a fresh utility knife on an old cutting board. I don't remember it being all that bad. Diferent but not that bad.


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## pdqdl (Aug 31, 2009)

Sure, fresh utility knife will do it. To bad you have to get a new knife blade after two or three cuts. It's not that I can't cut it at all, I'm just tired of replacing all the blades.


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## pdqdl (Aug 31, 2009)

outofmytree said:


> Sharp knife on a log is fine for beeline guys. Icetail I have no idea. Frankly I want my prussik cord to be hard to cut!



As hard as it is to cut with a knife, it won't stand up to a chainsaw. I took my first splicing attempts with the Beeline and made a saw lanyard with it. I got careless one day, and it exploded into a fluff of "no longer attached" where the chainsaw connected.

That was the first lanyard I ever cut off, so I can't compare to more conventional ropes in that size bracket. I guess it put up as much fight as my 1/2 stable braid rope did on a different day in much different conditions.


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## outofmytree (Aug 31, 2009)

I agree. Beeline is in no way saw proof even hand saws for that matter. Just hard to cut unless your knife is sharp and you cut onto something softer like wood.


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## Slvrmple72 (Aug 31, 2009)

Mallet, 1" carpentry chisel, electrical tape, and a big ol' chunk of wood. Press the chisel down hard and give it a good smack with the mallet. I get a nice clean cut everytime. Now when it comes to splicing.... I may have to make a trip to Ghillie cuz I am just not doing it right!

Moray, great posts! What hitch do you use when climbing?


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## Ghillie (Aug 31, 2009)

Slvrmple72 said:


> Mallet, 1" carpentry chisel, electrical tape, and a big ol' chunk of wood. Press the chisel down hard and give it a good smack with the mallet. I get a nice clean cut everytime. Now when it comes to splicing.... I may have to make a trip to Ghillie cuz I am just not doing it right!
> 
> Moray, great posts! What hitch do you use when climbing?



I will have to try that. I need to splice some icetail for my girlfriends son. He's really interested in climbing and so far he seems to be catching on quickly.

Be glad to share any knowledge I have (or think I have) SilverMaple.


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## outofmytree (Sep 1, 2009)

Slvrmple72 said:


> Mallet, 1" carpentry chisel, electrical tape, and a big ol' chunk of wood. Press the chisel down hard and give it a good smack with the mallet. I get a nice clean cut everytime. Now when it comes to splicing.... I may have to make a trip to Ghillie cuz I am just not doing it right!
> 
> Moray, great posts! What hitch do you use when climbing?



Sweet. I am gonna do this tomorrow. Great tip.


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## moray (Sep 1, 2009)

Slvrmple72 said:


> Mallet, 1" carpentry chisel, electrical tape, and a big ol' chunk of wood. Press the chisel down hard and give it a good smack with the mallet. I get a nice clean cut everytime...
> 
> Moray, great posts! What hitch do you use when climbing?



Great idea about the chisel--never thought of that. I like the Schwabisch, usually 3 over 2. I use a long tress cord, so the thick spliced parts of the Ice Tail don't contact the climbing line at all--it's all single-thickness.


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## moray (Sep 1, 2009)

*Pictures*

Here are some pictures of my hydraulic testing rig. This first picture gives a view of the whole. The first and one of the toughest design problems is to come up with a very sturdy framework to withstand all the pulling forces. A multi-ton steel framework would be very nice, but money-wise way out of reach. Two big trees separated by about 20 feet would be fine, but I was afraid of damaging my live trees, and I didn't have a pair of dead ones that would work. So I chose a large butternut log with some big branch stubs still attached. The log is easily strong enough to withstand the forces, up to 10,000 lbs, and it is stiff enough that it stores very little energy that I need to absorb during recoil.


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## moray (Sep 1, 2009)

The anchors are shown in these two photos. The slot at the lower anchor is somewhat rounded so that the chain can move in the slot. The chains are 20-foot lengths of G70 3/8-inch transport chain. Each one is always set up as a loop to minimize stress on the chain.


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## moray (Sep 1, 2009)

The upper chain is connected to a very large shackle, which is connected to the load cell. The load cell is then connected directly to the closed end of the cylinder. This connection introduces an error of 2 lbs or so in the readings, so it would be preferable to have the load cell connect directly to the experimental rope. That is a very dangerous place to be, so to protect the load cell I always connect it as shown.


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## moray (Sep 1, 2009)

The readout for the load cell is covered with a cardboard box with a porthole carved in the side. Thus shaded, it is very easy to read even in bright sunlight. All these pictures were taken while the test piece had 100 lbs. tension applied to it. A nice feature of the digital meter is that it stores and shows the highest reading it has received since the last reset. Thus after the rope breaks, the meter continues to show the force applied at the failure point.


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## moray (Sep 1, 2009)

The cylinder is rated for 3000 psi and has a 24-inch reach. It is always used in retraction mode, so the right-hand port is covered with a couple of layers of cloth to keep out the dust but allow air to pass. At 3000 psi the cylinder would be pulling just over 10,000 lbs. The 5:1 tackle on the rug is used to pull the cylinder back out after a test. It is not strictly necessary but makes the job easy.


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## moray (Sep 1, 2009)

The pump is well matched to the cylinder and is rated to produce 3000 psi. There is a way to change the mechanical advantage of the pump arm, but it is clunky and I have never tried to do it during a test. I will need to do it for anything above about 8,000 lbs. The pump is bolted to the wooden platform--without it it would fall on its nose. The hydraulic hose is 7 feet long and keeps me well away from the danger zone.


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## moray (Sep 1, 2009)

The pump and cylinder are ready to stow. All this stuff is heavy and clunky, so I leave it outside under a tarp unless I plan to be gone for a long time.


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## moray (Sep 1, 2009)

Knots being tested in a brand new piece of Bandit (Blaze). I think the big shackles have a WLL of 12 tons.


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## stihlhere (Sep 1, 2009)

*moray*



moray said:


> After the gauge reached about 9800 lbs., the next pump stroke took the read-out out of limits, and the stroke after that broke the rope. .



moray FIRST thanks for the TIME AND PICKS.
NOW on to loadcell be very carefull taking your load cell out side of max range you will distort it and after that it's junk. And dont even wast your time having it rebuilt. I've changed out more of those than I care to mention even seen some visibaly bent. also NOT THAT YOU WOULD only apply load in intended direction.

thanks so much for the info as i have been wanting to go to a prusik cord have tested any beeline?


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## outofmytree (Sep 2, 2009)

Hey mate.

As always, kudo's for the work. Rep coming your way as soon as I can. 

Stihlhere if you search morays thread you will find much beeline work.


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## stihlhere (Sep 2, 2009)

yea only had about 5 min yesterday check out thread and stopped when i got to the loadcell. I hate to make comments with out reading whole thread but had no time and wanted to throw that out about load cell. now on to search for bee line. thanks again a your efforts are very appreciated!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:yourock: moray


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## Adkpk (Sep 2, 2009)

I just started using Ice Tail e2e for my lanyard. It works much smother on the three strand than the Tenex. 

Great thread moray!


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## moray (Sep 3, 2009)

stihlhere said:


> ...NOW on to loadcell be very carefull taking your load cell out side of max range ...go to a prusik cord have tested any beeline?



Thanks for the warning. As it turns out, it is probably impossible for me to overload the load cell or the cylinder--both are rated to withstand 150% of their ratings. The most I have reached so far is 80%.

I haven't yet tested any Beeline, but I intend to one of these days. I know a lot of people use it. Ron reported some Beeline tests here:


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## ray benson (Sep 3, 2009)

I see you are also knot testing. Has anyone tested a Bowline on a Bight, Figure 9 or Alpine Butterfly? I have used the Bowline on a Bight when putting a loop in the middle of a rope for tensioning a tree with a truck. Curious if the other 2 knots are stronger/better suited.


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## pdqdl (Sep 3, 2009)

I read that report. Some of those numbers just don't make any sense. Especially the cover testing stronger than the core. Why not make it twice as strong by splicing with Class 1 (of course it is too tight a cover to make such a splice).

WHY, since the cover is "used" in the double overhand knot test, does the Beeline test at less than 1/2 of the rated strength?


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