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tugboat
Jul 19, 2011, 5:58 PM
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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....
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tugboat
Jul 20, 2011, 4:57 AM
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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.
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moose_droppings
Jul 20, 2011, 5:21 AM
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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.
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tugboat
Jul 20, 2011, 5:51 AM
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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 interest
Besides.... i love busting stuff! so please, help me indulge my obsession
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TarheelJD
Jul 20, 2011, 2:23 PM
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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.
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dynosore
Jul 20, 2011, 2:29 PM
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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....
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TarheelJD
Jul 20, 2011, 2:37 PM
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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.
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jbrown2
Jul 20, 2011, 2:55 PM
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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)
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tugboat
Jul 20, 2011, 4:33 PM
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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....
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TarheelJD
Jul 20, 2011, 4:37 PM
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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.
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tugboat
Jul 20, 2011, 4:57 PM
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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....
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TarheelJD
Jul 20, 2011, 5:04 PM
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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
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tugboat
Jul 20, 2011, 6:01 PM
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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?
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TarheelJD
Jul 20, 2011, 6:03 PM
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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.
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tugboat
Jul 20, 2011, 8:00 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 off
ps how do i get the images to self view in the message rather than just sit as atachments
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TarheelJD
Jul 20, 2011, 8:15 PM
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That looks perfect.
You might want to use steel biners for the 8mm test, you might break those.
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tugboat
Jul 20, 2011, 8:39 PM
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hmmm....gotcha...
have to dig up my steal carabiners you figure eh?
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TarheelJD
Jul 20, 2011, 8:41 PM
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Probably not for the 6mm cord but likely for the 8.
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tugboat
Jul 20, 2011, 8:59 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.
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tugboat
Jul 20, 2011, 9:05 PM
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ok...off to test....
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tugboat
Jul 21, 2011, 12:50 AM
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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 practice
that was with 6mm cord.
(This post was edited by tugboat on Jul 25, 2011, 5:46 AM)
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TarheelJD
Jul 21, 2011, 1:09 AM
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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.
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tugboat
Jul 21, 2011, 3:01 AM
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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 21, 2011, 3:02 AM)
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patto
Jul 21, 2011, 10:23 AM
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Registered: Nov 15, 2005
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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.
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