Splicing 101 - Tenex

[moray]

Compared to the vast amount of discussion on ArboristSite about knots, very little is said about splicing. My guess is the vast majority of people, even here on AS, have never spliced a rope; until a couple of years ago I was among them.

The idea of this short photo tutorial is to demystify the procedures for probably the simplest of all splices and maybe prod a few people to give it a try. Just as a beginner can tie a bowline that is as reliable and pretty as any tied by a pro, a beginner's first splice, carefully made, will be as reliable as any made by a pro. The pro, of course, will have made 10 of them by the time you finish your first, but yours should be just as strong.

We will make an eye splice in 3/8 in Tenex TEC, or so-called "sling grade" Tenex, the 12-strand hollow braid polyester rope made by Samson. The "TEC" stands for Two End Carrier, which means each strand consists of two yarns. In the photo below, the pink rope is Tenex TEC and the yellow rope is ordinary Tenex. They are slightly different. Ordinary Tenex is not as pliable and it is not quite as roomy in the center. The pliability of Tenex TEC makes it good for eye-and-eye split tails, but it is also widely used for whoopies, loopies, continuous loops, what have you.

The materials we need are minimal:

A few feet of 3/8 in. Tenex.
Vinyl electrician's tape.
Scissors.
Marking pen.
Large sewing needle with big eye.
Strong thread, or yarn from old rope.

 

[moray]

Layout

Referring to the schematic below, the idea of the 12-strand eye splice is very simple: insert the taped end of the rope in the side of the rope at E2, pull it down the hollow center of the rope toward D until E1 has reached the entry point, E2, and the splice is done. The Chinese finger cuff action of the main rope grabs the buried core sufficiently hard to prevent it pulling out under any load.

E1 and E2 are arbitrary points that define the size of the eye. The eye can be any size, but in this example we will make a tight eye to fit on a carabiner, as if for an eye-and-eye split tail. Whatever the size of the eye, the distance from E1 to the end must be 2 fids, and we make mark A at a distance of 1 fid. As the diagram shows, the distance from E2 to D is 2 fids.

How long is a fid? It is defined as 21 times the diameter of the rope. In the case of the 3/8 in rope we are using, this would be 7 7/8 in--call it 8 inches. The layout shown will work for any diamter of Tenex.

 

[moray]

Two major misgivings people have about splices concern (1) strength and (2) reliability. As to strength, tons of studies have shown a properly made splice will outperform any knot: splices consistently deliver 90% to 100% of rope tensile strength. I have pulled two splices to destruction myself using a big truck and a compound pulley setup. In both cases the splices remained completely intact, and the breakage occurred at the extreme tip of the splice's buried core.

The reliability question is a tougher nut to crack. There is some cold statistical comfort in knowing that someone has used splices for many years and never had a problem. But maybe during all those years the splice user was skating close to the edge, and dozens of times those splices were on the verge of pulling apart. REAL confidence in a splice would come from knowing it is vastly overbuilt and has no chance of coming apart.

I decided to test the 3/8 Tenex.

In the picture above, the spliced eye has a very short buried section and no taper at all. As the picture indicates, the manufacturer-specified length of bury is 16 inches, 8 of which is tapered. I did 3 pull tests with my car. With a 3-inch bury, the splice didn't budge. Wow! This was considerably better than I expected. I carefully pulled out exactly 1 inch of core, leaving 2 inches of bury, as shown in the picture. A hard steady pull with the car again left the splice unfazed. Defeated again. Carefully I reduced the bury to exactly 1.5 inches. The splice survived several seconds of hard, steady pull and then pulled apart--my very first experience of a splice pulling apart!

I did one other pull test, this one on a splice made with just the tapered part of the core, ie., the stretch from A to the end. Many people think the tapered part of the core contributes little or nothing to the strength of the splice. It is almost certainly not necessary for the splice to be reliable, but it supplies lots of friction. As expected, I could not pull the splice apart with the car.

 

[moray]

The last segment of the rope from A to the end will be tapered, and we begin that process before starting the actual splice. Note the 3 arrows. They indicate 3 marked strands (pairs of yarns) separated from each other by an unmarked strand. Three sister strands below those are similarly marked. Note that the right-most marking is just touching the mark A. There is nothing particularly critical about this. Just pick any strand at A and mark it. Then lay out 5 more marks so they occuply the pattern shown.

Next remove the tape at the end. One by one, starting closest to the end, lift the marked strands with fingernails or a sharp object of some kind, and pull the strand free from the end of the rope. The result is shown in the next photo.

Tightly tape the rope about 1/2 inch from the end. Then trim the end with scissors so that about 1/4 inch of bushy yarns extends beyond the tape. Do NOT tape all the way to the end of the rope! The bushy tip helps prevent the tape from snagging anything.

 

[moray]

We are ready to begin the splice. The first photo shows how you can push the rope together to bunch it up and loosen the weave. This also greatly expands the space inside the rope. We need this property over and over again to make the splice.

The tight tape near the end of the rope and the expanded brushy tip together constitute a mini-tool of sorts that allow us to perform the splice without any kind of special splicing tool. Holding the tape between thumb and forefinger, and holding the rope mildly bunched up at E2, work the brushy tip into the side of the rope at E2. It helps to sweep the tip side to side to move strands out of the way and enlarge the hole. When the tip is past all the surface strands and resting against the inner wall of the rope on the far side, angle the tip sideways and start to push it towards D (next photo).

The above described procedure is the heart of this whole thing and it is slightly tricky. Nevertheless, I snagged two people off the street who had never spliced a rope in their respective lives, and both were able to pull it off in somewhere between 1 and 5 minutes. I did about 10 in a row this morning, and got my average time down to somewhere between 5 and 10 seconds. You get better with practice.

It is vital not to insert the tip between 2 yarns in a single strand. It is also important that the rope not be twisted between the tip and E2, as this would result in a twisted eye. It is possible to get any such twist out later, but better not to put it in there in the first place. Since everything to come hinges on a clean insertion in this step, it would be worth practicing this step a few times to experience the potential pitfalls.

More to come...

 

[(WLL)]

now give dbl braid a try and 16st as well its not like tenex or any hollow braid but more fun and challenging. i do like what your doing and hope you keep going at it. nice pics

 

[moray]

You're right. I have done them both, and they are MUCH more challenging.

 

[moray]

Performing the bury consists of milking the tip down the rope away from the eye. It is the same action a python peforms when swallowing prey. You bunch up some rope and push it over the tip toward the eye, then pinch the tip through the cover while milking the cover slack toward the eye. It gets much easier and faster after a couple of inches have been buried.

When the loose strands are about to enter the rope, as shown above, cut off all the loose strands about 3/4 inch from the rope. This will keep the braid intact and not interfere with the splice in any way.

Continue swallowing the core until the tip reaches D. Open the strands at D with your fingers and work the tip out, as shown in the photo.

Finally, pull the tail hard and push the cover toward the eye. You can easily pull far enough to get A to emerge from the rope. The buried core is now so loose in the cover you can readily remove any twist in the rope.

 

[moray]

To make a tight eye such as this, it is helpful to form the eye around the carabiner. Size the eye just the way you want it, then make several passes with your hand to milk all the cover slack away from the eye. Most of the core will be sucked back into the rope.

This is the time to stitch the eye. We stitch it now so we won't disturb it later. The reason for stitching in the first place is to prevent a human or your dog from pulling it apart. It is not to give it strength or to carry small loads, as sometimes stated.

Even though Samson calls for using very heavy yarn, as heavy as the yarns in the rope being spliced, I use some much smaller polyester yarn from an old 3-strand rope. Just remember what it's for--the splice will work perfectly well with no stitching at all. Staying close to the throat of the eye, put about 4 stitches through the rope in one plane, rotate the rope 90 degrees, and put in 4 more back to the starting point. The needle on the last stitch should exit the rope at the original entry point.

Tie the two yarns together with a surgeon's knot or something, then use the needle to bury the tails obliquely through the rope, as shown. I have never had any stitching work loose.

 

[moray]

With the eye throat safely stitched, we are ready to finish tapering the tail. Once again milk all slack away from the eye so the tail has sucked in as far as it will go. Carefully mark the tail where it exits the rope as shown in the photo below. This mark represents the end of the buried core in the finished splice.

Pull the core out several inches once again so we can finish tapering the core. Cut the tail off about 1/4 inch to the eye side of the mark. This will guarantee that the tail will suck all the way in the next time we bury the core.

 

[moray]

Finishing Up

To make the final taper, first ravel the yarns at the end, starting roughly at the point of the awl.

In your mind's eye, divide the interval from the awl to the end of the tail into 5 equal intervals. This can be very rough. Cut two of the yarns right at the awl, two more 1 interval closer to the end, and so on, leaving the final two uncut. This gives a smooth 6-step taper as shown below.

One more step. Milk the cover away from the eye one last time. All the tail will get sucked into the rope and the splice is done.

 

[Adkpk]

This splice holds only by the core squeezing the sheath? I don't have my gear here but I would be interested in the factory splice on my tenex. Is it the same?

 

[(WLL)]

i recomend using the bremble lock or whatever ya call it

 

[moray]

This splice holds only by the core squeezing the sheath? I don't have my gear here but I would be interested in the factory splice on my tenex. Is it the same?

It is the same. Having the factory do it, in my not-so-humble opinion, is like having the factory tie an overhand knot for you!

 

[moray]

i recomend using the bremble lock or whatever ya call it

Brummel. You know, WLL, I have yet to see anyone give a good reason for the Brummel. It will "lock" the splice, but so will simple stitching. It can't supply anywhere near as much friction as the same length of proper splice. The only possible advantage I can see would be if it can essentially replace the buried part of the splice, allowing an extremely short overall splice. I would love to test the strength of a Brummel with short bury compared to a normal splice, but I don't have the honking big equipment I would need. Maybe someone knowledgable out there has the answer to this?

 

[Job Corps Tree]

Splicing 101

I think a Lot more may splice rope for them selves than you may think. To do it for yourself, you will be the one to use it, you don't have to worry about someone else getting hurt for what ever reason. I have made my own split tails sense split tails. I do my own Double Brade splices for what ever I may need. Eye-splice in my climbing line, Tenex if I want a Whoopie Sling or a Loppie Sling. I can make it. But it is still for me. I have not sent in Samples to any Manufacturer. I could, I may become Certified in that type of line but only that one line. This may be just a little bit stingy but if something go's wrong it's on me . Some of the 3 strand splices I may have done 10 0r 12 Years ago I ripe them apart now just to see where it will break. It once was my Flip line now it is a Choker same for all. I stress them on what I will be using them for . It says 10,000.LBs I will put a Truck on it and pull and than only use it 1000LBs. Love to Splice But for me

 

[Industry]

Is Ice the same as tenex for splicing?

 

[moray]

Is Ice the same as tenex for splicing?

Basically yes. Samson specifies using the locked Brummel with it (you may have to look around their website to find the correct instructions), but other than that it's about the same. It's not quite as easy to work with, but far from hard. I use it for my split tails.

 

[(WLL)]

Brummel. You know, WLL, I have yet to see anyone give a good reason for the Brummel. It will "lock" the splice, but so will simple stitching. It can't supply anywhere near as much friction as the same length of proper splice. The only possible advantage I can see would be if it can essentially replace the buried part of the splice, allowing an extremely short overall splice. I would love to test the strength of a Brummel with short bury compared to a normal splice, but I don't have the honking big equipment I would need. Maybe someone knowledgable out there has the answer to this?

i like the brummel because i feel a little better hanging my life on it other than that it is extra and i think it does take some strenth away from the rope. the stuff is so easy to splice it makes me feel better with the brummel lock. all the hollow braid splices i got from sherrill all had the brummel.

 

[Industry]

Basically yes. Samson specifies using the locked Brummel with it (you may have to look around their website to find the correct instructions), but other than that it's about the same. It's not quite as easy to work with, but far from hard. I use it for my split tails.

I just started using it and it already is getting "cooked". I did 3 descents from 10-12' with it and it is all black and starting to get some (tiny)frays. Is this normal?