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Construction and pull testing of specific itmes.
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tugboat


Jul 19, 2011, 10:58 AM
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Construction and pull testing of specific itmes.
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Hello all,... as things are somewhat slow in my industry right now....i offer up my sewing and pull testing facilites for anyone wishing to see a specific item tested. If you have items you want pull tested you can send them to me...or if you have a specific piece of sewn gear you would like to see built and busted, i can do this too.

My equipment includes; 18 foot long, engineered, testing bed with sensotronic load cell (good for 10 000lbs working load), GSE data aquisition, JUki progamable bartacker with a 20mmx40mm field, pfaff138, consew long arm 3 step walking foot zig zag, 280ly needle feed, Sunstar open arm binding attachment machine. Materials include all sorts of mil spec webbings from 1/4" to 3", spectra webbing and threads and broadcloths, etc, High def, 60fps
In reply to:
camera for video of pull tests. I have about 15 years of safety sewing experience under my belt....
Just putting it out there. If things are slow, perhaps i can entertain someone's needs,... as things get busier i may not have time. For now...things are slow.


tugboat


Jul 19, 2011, 9:57 PM
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Ps.... this is a free offer both for the building and the testing.

Suggestions for things to break are welcome and encouraged....

Im sure many items have been broken and analyzed here,...but if there is anything that i can offer to the communities pool of knowledg, i am very willing.Wink


moose_droppings


Jul 19, 2011, 10:21 PM
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Could you pull all of adatesman's post on this subject out of the toilet.

Just kidding.
Nice to have another tester aboard, and thanks for your offer.


tugboat


Jul 19, 2011, 10:51 PM
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Re: [moose_droppings] Construction and pull testing of specific itmes. [In reply to]
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If i hadn't glanced thru all the "happenings" of the last year on this board, i wouldn't have had a clue what your tallking about. But i did... and so i must respond; "no" sorry Moose Droppings, i don't think i can pull all that stuff from the abiss....besides i dont think my load cell would know what to do with it! Funny though!

I don't purport to have the knowledge that some of the individuals have on here, thats for sure..... but i do have equipment, supplies and willingness to help.

So i will accomodate requests as best i can if there is any interestSmile

Besides.... i love busting stuff! so please, help me indulge my obsessionTongue


TarheelJD


Jul 20, 2011, 7:23 AM
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I love to see the results from pull tests -- reminds me of days in the engineering lab.

I would love to see a pull test of a quad as described in JL's anchor book. Basically a 4 stranded equalette. I make mine out of 8mm nylon cord with a double fisherman's knot and then overhand knots about 12 inches apart as limiting knots. I am really curious to see where the failure point in this would be.


dynosore


Jul 20, 2011, 7:29 AM
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TarheelJD wrote:
I love to see the results from pull tests -- reminds me of days in the engineering lab.

I would love to see a pull test of a quad as described in JL's anchor book. Basically a 4 stranded equalette. I make mine out of 8mm nylon cord with a double fisherman's knot and then overhand knots about 12 inches apart as limiting knots. I am really curious to see where the failure point in this would be.

Then send him some 8mm cord....


TarheelJD


Jul 20, 2011, 7:37 AM
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If tugboat doesn't have any spare cord laying around for destruction purposes I could mail some. Or paypal him for the costs of some since shipping would probably equal or surpass the cost of cord.


jbrown2


Jul 20, 2011, 7:55 AM
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id love to see how strong a really flattened out rope is. (you know, the end of the rope you cut off that gets flat from falling and lowering on it)


tugboat


Jul 20, 2011, 9:33 AM
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no worries....i have 8mm cord,..... dont know that i have any flattenened out rope. But i have rope,.... and i have a hammer....Wink


TarheelJD


Jul 20, 2011, 9:37 AM
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Sweet. Here is a clarification of the quad test: If I'm setting a quad at a two bolt anchor I normally clip the rope-side biners into three of the four strands between the limiter knots. I'm guessing that it will break at one of the knots.


tugboat


Jul 20, 2011, 9:57 AM
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ok.... first let me get some coffe in my blood stream (just woke up)..... then i'll have to get my head around your anchor setup. I use to be a dirt bag, yosemite, squamish, climbing fool. But now im just a fool that hasn't climbed in years; you know, got hitched, got animals, got a belly.....then i discovered paragliding and that pretty much put a nail in climbing's coffin. Once my poor old shop dog (he has cancer now) passes on, i may get back up to squamish....


TarheelJD


Jul 20, 2011, 10:04 AM
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No rush at all, take your time.

Here's a picture I found, should be pretty self explanatory:

http://img480.imageshack.us/img480/501/quad6dq.jpg


I realize that the test might not be super real world since the the angle between the two legs will be greater in a two bolt belay but I can back calculate the strength for a given geometry once I know the breaking strength when there is no angle.

Thanks again


tugboat


Jul 20, 2011, 11:01 AM
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ok...yup....thats the image i found too.... So rigging that of my anchor plate, given the shallowness of the angles is ok......ok. I may have a solution to rig to a wider angle.... i guess somewhere in the area of 45 degress would be nice if possible eh?


TarheelJD


Jul 20, 2011, 11:03 AM
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I think anything from 30-45 would work well. I don't have access to any cord right now (not home) so that is just a visualized guess.


tugboat


Jul 20, 2011, 1:00 PM
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OK....So like this?.... I see in the other pic you showed me that the fellow grabbed two strands seperatley with each rope side biner. As you can see,...that would be the rigging plate i would use to make life easy for me to rig at the anchor end of my test bed. I do have an "ariel" spreader bar for "performers"...but im not sure i want to risk it on this test.

Also the cord in these pics is 6mm. Its what i had at home (where my pull tester is). I thought i would do a prelim test pull with that.... or would you prefer 8mm straight up?... I'll have to go buy some=reason to go look at goodies at the climbing shop....so no worries.Im thinking with 6mm the break could be over the bolt carabiners given smaller radius than 8mm setup?

Also...what about biner selection at the pins and at the rope end? probably doesn't matter.

Let me know.... I may just go do this test now before the coffee wears offTongue

ps how do i get the images to self view in the message rather than just sit as atachments
Attachments: IMG_2796.JPG (94.0 KB)
  IMG_2797.JPG (97.5 KB)
  IMG_2798.JPG (92.2 KB)
  IMG_2799.JPG (81.8 KB)
  IMG_2800.JPG (82.8 KB)
  IMG_2801.JPG (80.4 KB)


TarheelJD


Jul 20, 2011, 1:15 PM
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That looks perfect.

You might want to use steel biners for the 8mm test, you might break those.


tugboat


Jul 20, 2011, 1:39 PM
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hmmm....gotcha...

have to dig up my steal carabiners you figure eh?


TarheelJD


Jul 20, 2011, 1:41 PM
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Probably not for the 6mm cord but likely for the 8.


tugboat


Jul 20, 2011, 1:59 PM
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Actually i'll just use my steel, extreme load, rigging shackles....they are stronger than steel carabiners. Just have to choose the right size to match biner diameters...

So in that case we will be ulitmatley testing the sling strength regardless of weather a biner would fail in real life scenario.

Maybe do both tests....more to bust! fun.


tugboat


Jul 20, 2011, 2:05 PM
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ok...off to test....


tugboat


Jul 20, 2011, 5:50 PM
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OK. Test completed and video taped. Will upload to you tube next. Break at the knot like you figured,...at just over 7000lbs. or approx 31 KNs.

Much bigger setup than i thought! oh well good practiceSmile

that was with 6mm cord.


(This post was edited by tugboat on Jul 24, 2011, 10:46 PM)


TarheelJD


Jul 20, 2011, 6:09 PM
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Wow. Nice results. Can't wait to see the video. Don't worry about doing the 8mm if you don't want to, the fact that the 6mm broke at 7000lb is pretty impressive.


tugboat


Jul 20, 2011, 8:01 PM
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Pull vid is being uploaded right now....butr because its fairly high def and my connection isnt that fast, it will take a while....

I did upload the video of the single 6mm loop break though...

http://youtu.be/JVEasE1pJJc

the quad video should be up in an hour or so...

peace...


(This post was edited by tugboat on Jul 20, 2011, 8:02 PM)


tugboat


Jul 20, 2011, 10:29 PM
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Here is todays pull of the requested "Quad Anchor"...

http://youtu.be/aUqy1F7uZKY


patto


Jul 21, 2011, 3:23 AM
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6mm Cord
[rating] x [number of strands] x [knot reduction]

7.5kN x 6 x.65 = 29.25kN


So it is entirely within expectations to break around 31kN.


TarheelJD


Jul 21, 2011, 5:59 AM
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Very nice. Thanks for doing the test. I figured it would break somwhere between the knots or at the knot. Granted in real world applications the bolt spacing would be further apart but this definitely gives an accurate enough picture of what a "quad" failing looks like. I would imagine an 8m cord would have a similar failure mode with just much higher forces involved, like double -- which would exceed the strength of just about everything else in the system.

Thanks again


tugboat


Jul 21, 2011, 10:27 AM
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Yup....no prob. It was fun.


"Next...."?


mambembe


Jul 22, 2011, 4:28 AM
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I would like to see the equallete tested. The real equallete, simulating an equalization of 4 pieces whit 4 clove hitches.
I suppose the point of failure will be the hitches and at lower force than the quad.

Sorry for the broken english.


tugboat


Jul 22, 2011, 11:20 PM
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I picked up some mammut 7mm cord today. And have more of the 6mm cord.

I found some hardware to simulate a multi point station that is about two feet wide.

I would enjoy carrying out your request.


(This post was edited by tugboat on Jul 23, 2011, 12:12 AM)


ncrockclimber


Jul 24, 2011, 10:49 AM
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Hey tugboat. Great work! This reminds me of what the lab was like at its best, just with a better personality.

I would like to see you test a double figure 8 / bunny ears knot. Specifically, I would like to see the knot set as you would at a 2 bolt anchor, weight the knot, then cut one of the ears. I have always thought that if one of the strands was cut, the anchor would completely fail. I know that this is not a common occurrence, but I am curious if this is the case.

An example of the knot can be found here:
http://www.chockstone.org/TechTips/BunnyEars.htm


tugboat


Jul 24, 2011, 11:28 AM
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Double eight anchor test. [In reply to]
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Ok....i understand your scenario. Some specifics though; i assume using the 11mm dynamic climbing rope as the anchor. Now how much weight on the anchor? and then nick the one eight or start with a 10% cut or ?.....

If your just going to want body weight then cut....i wouldn't think the anchor will fail. But i think you want 'heavy weight' the anchor then pull to destruction.

I use to use the double eight alot when i climbed.


(This post was edited by tugboat on Jul 24, 2011, 7:43 PM)


tugboat


Jul 24, 2011, 12:04 PM
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Can someone send me a pic of the setup "mambembe" would be wanting. There seems to be so many variations on the theme of "true equillete" when i research it. So what would be considered the true equillete as he describes? When i climbed i mostley tied in with the rope.... i wasn't as much into building guide sling stations as i found them time consuming. And my game was light and fast multi pitch. So i am not as well versed as many of you in the varieties of anchor setups. I went to buy JL's anchor book from MEC the other day but they were sold out.


Is the attatched image what he would be considering?[/image]


(This post was edited by tugboat on Jul 24, 2011, 3:49 PM)


acorneau


Jul 24, 2011, 2:28 PM
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Yes, that's the original equalette.


tugboat


Jul 24, 2011, 3:51 PM
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thanks acorneau. I'll set it up then for his request. I think the static mammut 7mm would be a good size eh?


mambembe


Jul 24, 2011, 4:23 PM
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Hey Tugboat,

Thats exactaly what I was looking for. Sorry I didnīt post a picture, I donīt know how.

7mm is a good size.

Thanks


tugboat


Jul 24, 2011, 11:36 PM
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Hey ncrockclimber.... I've been thinking/looking over the ' bunny ears' knot and have formed some ideas regarding possible outcomes and issues with making the test worth any real world reflection;

1st off, i believe the most important determining factor of total anchor failure would be where one of the "bunny ears" breaks. In forming the knot, the pass over loop to form the two ears, effectively makes two independent loops that would pass a pull if neither loop was cut. But when you cut one or the other loop near the hanger...the remaning loop effectively becomes a bowline around the original figure eight. The bowline is formed around double strands rather than a single strand of rope, thus increasing bite radius. Now, if the bite is not effected by the double strand radius and the break left enough "tail"...then i believe you would have a fully functioning bowline for an anchor left over. The remaning pull would eventually break at the bowline knot.

This brings us to #2) Is there a scenario (other than a cut in the rope) that would leave us with a break far enough away from the main knot?...so we have enough bowline tail?

then #3) i do believe, that the use of this anchor usaully leaves the belayer tighed in to the rope and off to one side of the belay ....the rope leading to the main knot. And the rest of the rope either is set for the 'jugger' or is belayed for the second. Here....the most likely case i would think would be a failure in the belaying and hence single strand loading of the main knot from below the 'ears'. Thus for a test should we not be pulling a single bottom strand for the rope end anchor?.

In conclusion, i think, the main test should be "what would happen if one of the ears (somehow....and unlikley) broke close to the main knot"?.....say from unequal loading of the loops? Then what could possibly happen, is that the lack of long enough bowline tails, would lead to 'pull through' (undoing) of the knot under load.

Anyone else want to chime in....am i off base on this guess? whacha think?


(This post was edited by tugboat on Jul 25, 2011, 1:15 AM)


tugboat


Jul 25, 2011, 12:33 AM
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some pics trying to show progression on loop break, to effective bowline, to progressive undoing of bowline:

1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)


(This post was edited by tugboat on Jul 25, 2011, 1:16 AM)


JimTitt


Jul 25, 2011, 1:43 AM
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One of the ears isnīt going to break since we donīt get high enough loads for that so itīs going to have to be a cut from a rock for example. This is a random effect so worst case is it cuts at the knot leaving no tail and the whole things fails.
Iīd be clove hitching into one anchor, into the other and back to myself to give two easily adjustable independent tie-ins like climbers have for generations.

Jim


ncrockclimber


Jul 25, 2011, 10:02 AM
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In reply to:
In conclusion, i think, the main test should be "what would happen if one of the ears (somehow....and unlikely) broke close to the main knot"?.....say from unequal loading of the loops? Then what could possibly happen, is that the lack of long enough bowline tails, would lead to 'pull through' (undoing) of the knot under load.

Tugboat, I think that is a spot-on summary of what i wast thinking about. To replicate a real-world scenario, I would first apply a 300 pound load, replicating a climber at a hanging belay and thus tightening the knot. Then I would cut one of the strands. If the know holds, start to apply more weight. I don't know if uneven loading makes any difference or not.

Again, I appreciate your contribution here and look forward to your next post.


Partner cracklover


Jul 25, 2011, 11:07 AM
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tugboat wrote:
Yup....no prob. It was fun.


"Next...."?

Hi Tugboat, you still have time to kill?

I have some fixed draws I pulled (and replaced) from a sport climb after discovering how worn they were. I'd love to see just how much they could have held.

GO


tugboat


Jul 25, 2011, 2:41 PM
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JimTitt wrote:
One of the ears isnīt going to break since we donīt get high enough loads for that so itīs going to have to be a cut from a rock for example. This is a random effect so worst case is it cuts at the knot leaving no tail and the whole things fails.
Iīd be clove hitching into one anchor, into the other and back to myself to give two easily adjustable independent tie-ins like climbers have for generations.

Jim

Oh....for sure...i agree Jim. Its just an analysis in refernece to the previous members pulltest request. More of a brain teaser than anything else. I like all the requests regardless of how unlikley they might be in real world scenario.Smile


tugboat


Jul 25, 2011, 2:42 PM
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cracklover wrote:
tugboat wrote:
Yup....no prob. It was fun.


"Next...."?

Hi Tugboat, you still have time to kill?

I have some fixed draws I pulled (and replaced) from a sport climb after discovering how worn they were. I'd love to see just how much they could have held.

GO

yup....no prob... i can bust em.

ill msg you my mailing address if you want them checked.


(This post was edited by tugboat on Jul 25, 2011, 10:36 PM)


cellige


Jul 25, 2011, 9:17 PM
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Hey tugboat,
Thanks for the free testing and especially for the results here. Its nice to see climbers give back, even if they haven't climbed lately !

I was going to suggest if you end up testing the equalette, I would love to see the "dorkalette" as seen in an adjacent thread in the Lab tested in the same manner. Especially the cases when a point of pro fails.

Also a strength test I would love to see out of pure geekdom would be the final tucked eight tie in knot that is so common today amongst the sport climbers. Does the extra diameter of that tail provide less strain on the first bend of the knot? Lets find out :D

Thanks again and let me know if you need cord or biners etc.


tugboat


Jul 25, 2011, 10:30 PM
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cellige wrote:
Hey tugboat,
Thanks for the free testing and especially for the results here. Its nice to see climbers give back, even if they haven't climbed lately !

I was going to suggest if you end up testing the equalette, I would love to see the "dorkalette" as seen in an adjacent thread in the Lab tested in the same manner. Especially the cases when a point of pro fails.

Also a strength test I would love to see out of pure geekdom would be the final tucked eight tie in knot that is so common today amongst the sport climbers. Does the extra diameter of that tail provide less strain on the first bend of the knot? Lets find out :D

Thanks again and let me know if you need cord or biners etc.

thanks for the kind comments,...your requests are noted. I'll put them on the listWink


tugboat


Jul 25, 2011, 11:02 PM
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Just so people looking for testing know... I do have time to spare these days for testing,... however my poor old dog, Tugboat, is living day by day with cancer. Generally, with medication, and lots of treats and love he has mostly good days still. However, as you could appreciate, since he is my only family and best friend, he comes first. Sometimes, out of the blue, i get tied up for a few days, full time, taking care of his needs. So tests might get put on hold all of a sudden for a couple days. Hope you all understand. But, be reassured, all requests will get carried out..... cause when it comes to 'bustin' stuff, i just can't resistWink




Partner cracklover


Jul 26, 2011, 7:43 AM
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Poor Tugboat! Good luck to you both, and of course we'll give you plenty of slack.

Cheers,

GO


ncrockclimber


Jul 26, 2011, 9:34 AM
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I think everyone will understand that Tugboat comes first. Best wishes to the both of you!


tugboat


Jul 27, 2011, 10:18 PM
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Got your pic cellige. Very interesting... never saw that back when i climbed.

I dont see the tuck back doing anything in terms of helping the strength becasue of any radius increase.

My main concern with knot would be; are the people using this leaving enough tail before they tuck back? Otherwise they might be thinking that the loading of the knot will cinch down the short tail to stop 'initial' knot load / tail slide. I personallly wouldn't want to put money on that idea. But thats what some testing would show. maybe check differnet tail tuck back lengths to see if short tail slip is an issue.

But if they are leaving a nice long tail and then tucking back, than i don't see any probs with this knot. They gain the advantage of cleaning up the rope/ knot so they dont have a fisherman's tie-off to get in the way for clipping draws.

Will test it out.




(This post was edited by tugboat on Jul 27, 2011, 10:23 PM)


tugboat


Jul 27, 2011, 10:43 PM
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Actually... playing with the knot, i can't imagine people would be leaving little tails to tuck back. It seems intutivley dangerous and not that easy to do. You actually have to work at producing a tiny length to tuck back. Its much easier to tie your knot with at least 4 inches and then tuck it back.....without much work. I hope thats what people are doing.


JimTitt


Jul 28, 2011, 12:23 AM
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If you want to horrify yourself tie the ends of two ropes together (like for rapping) and tuck BOTH ends back exactly as in your picture. Then pull the two ropes apart, you donīt need to put this one on the tester!
And yes, it was fatal.

Jim


tugboat


Jul 28, 2011, 12:29 AM
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In reply to:
so they dont have a fisherman's tie-off
....i should have said overhand knot....


tugboat


Jul 28, 2011, 12:38 AM
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In reply to:
If you want to horrify yourself tie the ends of two ropes together (like for rapping) and tuck BOTH ends back exactly as in your picture. Then pull the two ropes apart, you donīt need to put this one on the tester!
And yes, it was fatal.

Jim, your not actually saying someone did that are you!?....crazy.

Reminds of climbing with a fellow whos 'hike down' shoes came flying off his carabiner/gear loop. I laughingly said "what did you do?....tie those on with a slip not?..."... unfazed, he replied, "...ah,...yes,...i did." He died climbing several years later.


tugboat


Jul 28, 2011, 11:43 PM
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Setup gear today to do "rabbit ears" and "yosemite finish"....hopefully get them busted for ya tomorrow. Then on to the dorkalette and original equallet. Had to get "Tugs" eating again... he decided the only food he wants now is the most expensive....wouldn't you know it!


sandstone


Jul 29, 2011, 6:37 AM
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Best wishes for Tugs, and thanks for your testing.


acorneau


Jul 29, 2011, 7:43 AM
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Hey Tugboat,

If you have time I would love to get a test on a standard two-point Triplette using 7mm cord, tied with overhands, and with two biners at the master point.

For reference here's a couple of pictures:

The second set of knots are not needed in this example:
http://www.rockclimbing.com/....cgi?query=triplette

This example has the left side split to two points, which isn't needed:


Also, sorry to hear about your puppy dog. Hang in there!


(This post was edited by acorneau on Jul 29, 2011, 7:48 AM)


sungam


Jul 29, 2011, 8:10 AM
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tugboat wrote:
Just so people looking for testing know... I do have time to spare these days for testing,... however my poor old dog, Tugboat, is living day by day with cancer. Generally, with medication, and lots of treats and love he has mostly good days still. However, as you could appreciate, since he is my only family and best friend, he comes first. Sometimes, out of the blue, i get tied up for a few days, full time, taking care of his needs. So tests might get put on hold all of a sudden for a couple days. Hope you all understand. But, be reassured, all requests will get carried out..... cause when it comes to 'bustin' stuff, i just can't resistWink

Hey an, sorry to hear about your dog. My dog has bone cancer in her leg and is feeling pretty rough.


Thanks for taking the time to pull-test. It's what the lab is all about. I think some problems could be avoided this time by not having you on the "staff". People seemed to get the idea that it was RC.com testing gear rather then a dude who happened to be a mod doing it. I remember one thread where someone asked for rc.com's official statement re: aliens.

Have fun bustin' stuff!


Partner cracklover


Jul 29, 2011, 8:53 AM
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tugboat wrote:
cracklover wrote:
tugboat wrote:
Yup....no prob. It was fun.


"Next...."?

Hi Tugboat, you still have time to kill?

I have some fixed draws I pulled (and replaced) from a sport climb after discovering how worn they were. I'd love to see just how much they could have held.

GO

yup....no prob... i can bust em.

ill msg you my mailing address if you want them checked.

Okay, the two dogbones are in the mail. USPS says about two weeks.

Maybe take a pic of each and post it here, and we can take bets on the breaking point of each?

GO


tugboat


Jul 29, 2011, 1:31 PM
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acorneau wrote:
Hey Tugboat,

If you have time I would love to get a test on a standard two-point Triplette using 7mm cord, tied with overhands, and with two biners at the master point.

For reference here's a couple of pictures:

The second set of knots are not needed in this example:
http://www.rockclimbing.com/....cgi?query=triplette

This example has the left side split to two points, which isn't needed:
[image]http://www.supertopo.com/photos/8/22/203749_31470_L.jpg[/image]

Also, sorry to hear about your puppy dog. Hang in there!

Added to the list!


tugboat


Jul 29, 2011, 1:33 PM
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cracklover wrote:
tugboat wrote:
cracklover wrote:
tugboat wrote:
Yup....no prob. It was fun.


"Next...."?

Hi Tugboat, you still have time to kill?

I have some fixed draws I pulled (and replaced) from a sport climb after discovering how worn they were. I'd love to see just how much they could have held.

GO

yup....no prob... i can bust em.

ill msg you my mailing address if you want them checked.

Okay, the two dogbones are in the mail. USPS says about two weeks.

Maybe take a pic of each and post it here, and we can take bets on the breaking point of each?

GO

Cool. they will be video'd like the other 'pulls'.


tugboat


Jul 29, 2011, 1:44 PM
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In reply to:
Thanks for taking the time to pull-test. It's what the lab is all about. I think some problems could be avoided this time by not having you on the "staff". People seemed to get the idea that it was RC.com testing gear rather then a dude who happened to be a mod doing it. I remember one thread where someone asked for rc.com's official statement re: aliens.

yeah,... i understand that. I have no financial vested interest or affiliation. Just equipment and the love of busting stuff!. And people should/will make there own judgements about stuff. I wish not to endorse nor advise anything. My testing should in no way be deemed definitive or even scientifically correct for the purpose of rock climbing; that, (if its not obvious) is my wavier of liabilityWink


edge


Jul 29, 2011, 1:50 PM
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Tugboat, thanks for all the work breaking stuff.

For the sake of clarity, maybe you could start a well titled thread for each new test so that discussions and searches will be more relevant to each particular project?

Cheers!


tugboat


Jul 29, 2011, 5:05 PM
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edge wrote:
Tugboat, thanks for all the work breaking stuff.

For the sake of clarity, maybe you could start a well titled thread for each new test so that discussions and searches will be more relevant to each particular project?

Cheers!

makes sense. will do.


dagibbs


Aug 4, 2011, 10:37 AM
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Can you do repeated lower-force loads?

I don't know if they have been tested before (probably?) but the simple overhand knot for joining two ropes for a rappel. Probably figure 8" tails or so.

A rappel is going to be far more of a repeated low (body weight plus a bit) load, rather than the high load of a fall.


tugboat


Aug 4, 2011, 7:24 PM
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dagibbs wrote:
Can you do repeated lower-force loads?

I don't know if they have been tested before (probably?) but the simple overhand knot for joining two ropes for a rappel. Probably figure 8" tails or so.

A rappel is going to be far more of a repeated low (body weight plus a bit) load, rather than the high load of a fall.

Hey daggibs. The low and high loading of overhand, fig eight etc on rappel have been thoroughly investigated on the web over years. As roy-jr-hinkley has pointed out. He is quite right. Given how long the setups take and my dog's illness, its probably not one i would get a around too currently. Do a search on "rappel accident/death" posted on rec.climbing (news) or 'tradgirl.com or at this website: very reasearched topic.....

goodluck.... any tests that you can't find covered or add further knowledge i could consider. Thanks for you inquiry.

my research on this topic has led me to wanting to see the "flipping or rolling" inside out of the overhand not etc when tied for rappel in certain setups. If i do i will let you know. But it is sort of a dead topic here.

peace,


(This post was edited by tugboat on Aug 4, 2011, 7:58 PM)


tugboat


Aug 4, 2011, 8:39 PM
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oh...and as regards "repeated" low loading testing; this is a very useful test in harnesses, gear, etc, since this is generally the usage they see. And low repeated loading can often be the variable that is more of a problem than high loading....especially in my field of work.

On that note,... i looked into a "cyclic loading tester" when putting my business together. My inquiries found that one would need a pneumatic setup that at the time wasn't reasonable for my facility or budget.

So, "no",....i can't do repeated low load testing that would give significant numeric results eg hundreds or thousands of pulls.


miklaw


Aug 5, 2011, 2:43 AM
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Real "SN" tests (stress vs number of cycles to failure) require thousands (or millions) of cycles and lots of specimens. A quick and dirty alternative is something I developed (and probably many before me) , The Block Test. If you know the failure load, start at 10% of that, give it 5 cycles, go up 5% in load and give it another 5 cycles, etc etc till it breaks.
We did a lot of tests on fixed anchors like this.
http://routes.sydneyrockies.org.au/display/thelab/Fatigue+testing
Attachments: fig%2031.jpg (50.4 KB)


tugboat


Aug 9, 2011, 9:03 PM
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Work has picked up,....so request are on hold for a week or so. But still on the burner.

Thanks all.


binrat


Aug 10, 2011, 12:32 PM
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tugboat wrote:
Work has picked up,....so request are on hold for a week or so. But still on the burner.

Thanks all.
Its good that work has picked up. Thank you for the tests that you have completed.


scrapedape


Aug 26, 2011, 8:00 AM
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How about testing of triaxial loading of carabiners?

We all know this is "bad," but do we know how bad it is?

This has been causing some friction over here in another thread, in which I have been, shamefully, a little too engaged: http://www.rockclimbing.com/..._reply;so=ASC;mh=25;

I would imagine testing triaxial loading would require some kind of customized testing rig to be set up, which might require some thought.


tugboat


Aug 26, 2011, 1:11 PM
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Ill check it out when work lets off the gas pedal a bit. Right now its pinned to the floor..... which is good...but very tired.

Cracklover's slings are next up to be broken. Then ill go from there.

Thanks for the suggestion.

Sorry to all those waiting on testing requests....but when work starts to fly i gotta run with it.

peace


Partner cracklover


Sep 9, 2011, 8:36 AM
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tugboat wrote:
Ill check it out when work lets off the gas pedal a bit. Right now its pinned to the floor..... which is good...but very tired.

Cracklover's slings are next up to be broken. Then ill go from there.

Thanks for the suggestion.

Sorry to all those waiting on testing requests....but when work starts to fly i gotta run with it.

peace

For those of you interested in checking out the dogbones I cleaned off a route - here's a link to the new thread (I only just noticed the new thread the other day): http://www.rockclimbing.com/...rum.cgi?post=2529000

GO


dindolino32


Oct 16, 2011, 10:21 AM
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Hey tugboat, I have a possibly new pull test project for you. I searched for this but using key words "fig 8 and carabiner" tend to give a ton of results so sorry if this has been tested already.
I have seen a couple of people at a nearby gym clip a biner IN the fig 8 knot to ease in untying the knot if a lead fall takes place. I never have practiced this as it would seem to compromise the integrity of the knot. Also, I am not sure whether it is clipped in the proximal loop or the distal loop compared to the harness tie in point. I assume the proximal would definitely be a problem. Any info would be nice to see.
Thanks
Dan


acorneau


Oct 25, 2011, 1:49 PM
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dindolino32 wrote:
I have seen a couple of people at a nearby gym clip a biner IN the fig 8 knot to ease in untying the knot if a lead fall takes place.

I've seen people put a biner in knots while rigging a top-rope anchor but never in someone's tie-in knot.

What if something like a quickdraw catches on the spare biner? Sounds sketchy to me.


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