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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 01:12pm PT
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Ed,
I could do about 10 of these test and establish some statistical significance.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 01:15pm PT
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Ed,
I will stick with the tests. I also know the theory quite well. I cannot comment on some of your wild speculations much!@ Like the "rock may get in tension etc"
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Ed Hartouni
Trad climber
Livermore, CA
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Apr 10, 2011 - 01:16pm PT
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I don't think that's a wild speculation, it is just Newtonian force analysis...
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 01:21pm PT
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Ed,
It seems you have missed some of the previous chatter.
Consult further my posting: Is this the elegant solution to safe anchors?
In that posting I suggest putting a device between two less safe anchors while still preserving a "no untie anchor".
The two preexisting bolts may sometimes be as close as say 4 inches apart.
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Mighty Hiker
climber
Vancouver, B.C.
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Apr 10, 2011 - 01:21pm PT
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This is all quite interesting - the collision of physics with engineering with real world with community 'norms'. I tend to agree with Ed - such information as there is suggests a healthy spacing be used.
a thoughtless Tea Bagger Isn't it redundant to use "thoughtless" and "tea bagger" in the same sentence?
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Ed Hartouni
Trad climber
Livermore, CA
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Apr 10, 2011 - 01:27pm PT
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for the purpose of full disclosure, I am among those who have used Dingus' sport anchors and I have absolutely no qualms about their security... and about the care that Dingus has taken to assure that these anchors are safe for their purpose
I especially like the "Ram's Horn" design, though it requires you to be able to understand concepts like "left" and "right" and so may disqualify some of our colleagues from safely installing them on routes
But sport anchors intended for top roping and lowering, for the most part, have a different set of requirements from those anchors on multi-pitch climbs that may also have to hold forces generated in high fall-factor falls, so it is not clear to me that the community benefits from any specific dogma concerning safe anchors
Also, we all depend on the anchor-placer to provide us with safe anchor placements, and we trust those anchors with our lives, literally... so more discussion is a good thing
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 01:28pm PT
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Ed,
so okay I will go along with the Newtonian physics.
Let's say the top of the borehole is 12 o'clock. The compression loading at the mouth occurs at 6 o'c and at 12 o'c in the back of the bore hole. At 3 oc and 9 oc at the mouth there could some resolving tension stress. But this is very small. In fact so small in my test that there are no signs of failure.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 01:36pm PT
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Ed and Mighty Hiker,
okay I will make known a failing in my description of my safe anchors statement!
It should have read: Is this the elegant solution for safe sport climbing Anchors?
The distance question arises when you get 2 existing bolts very close together.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 01:43pm PT
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Mighty Hiker,
There are a lot of posers out there. I once ask to speak to a Hilti tech engineer. The guy was not an engineer but at first said he was one. When he realized he could not answer my question he gave me the # of an engineer. This guy said he could only quote their manual. The info would help in the design of rock training course I was hired to build for a Summer Camp. I called my friend Tom Kelly a climber and rock engineering consultant and we hashed out a solution.
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High Fructose Corn Spirit
Gym climber
Full Silos of Iowa
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Apr 10, 2011 - 01:48pm PT
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The guy was not an engineer but at first said he was one.
I hate that.
And there should be a law agaist it.
Just as there is for doctors.
Damn it.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 01:52pm PT
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Ed,
I have heard physicist say "let's do a thought experiment." It certainly seems a lot of your speculation was a though experiment without much detail?
But though experiments hold no candle to seeing how bolt/borehole destruction really happens as loading occurs.
Is my loading too slow? I could drive the van against these anchors.
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Ed Hartouni
Trad climber
Livermore, CA
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Apr 10, 2011 - 02:02pm PT
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I've thought a lot about the "dynamic" nature of climbing falls and I think that given the rate these things occur at that they are essentially static, for the purpose of material response, etc...
so I wouldn't think that a fall load is so different from a static load, especially in the sport-climbing application....
we all know (I think) that the "stiffer" the anchor system (including slings, ropes, harnesses, bodies, belay devices, etc.) the higher the forces, but aside from that there is nothing special about how that force is generated... true "shock" behavior only occurs when the forces change over a time short compared to the distance over which they are applied divided by the speed-of-sound in that material... and for climbing that never happens.
by the way, that sort of "thought experiment" helps you narrow your investigation and guide your experiments to those that are essential, and in the end helps to correctly generalize, and more importantly, state the limitations of those generalizations.
otherwise, you are just testing over all the possible situations, and interpolating between the results, which might be fine until you have a situation that does not exist within the domain of your tests
but I agree that the best situation is to confront "theory" with "experiment," the combination of the two is more powerful than either one taken alone
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apogee
climber
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Apr 10, 2011 - 02:09pm PT
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"..a thoughtless Tea Bagger Isn't it redundant to use "thoughtless" and "tea bagger" in the same sentence?"
heh heh
This thread is much more compelling when it stays relatively clear of ad hominems (unusual for ST, I know). Critical observations are useful to the dialogue- don't take them too personally.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 02:14pm PT
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Mighty Hiker,
your first reference corroborates what I have said about hammer taping to determine sound rock for bolting anchor locations.
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Crimpergirl
Sport climber
Boulder, Colorado!
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Apr 10, 2011 - 02:18pm PT
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Thanks Dingus.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 02:22pm PT
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apogee,
I took a course from the Teaching Company -- Argumentation the study of effective reasoning. They contend that mild ad hominems have become acceptable when the fact are clear.
It seems that at the begining of post all the wingnuts come out of the woodwork.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 02:27pm PT
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Ed,
You are right.
In general as long as your real loading situation speed does not exceed the shock wave speed of the material or gu, any slow rate of loading is adequate for the experiment.
Yes we both do thought experiments making use of symmetry and by doing this we decide in what manner to run a real test effectively.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Apr 10, 2011 - 02:37pm PT
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klk,
esp. since almost none of the sport areas i climb at involve vertical walls or good rock. steep choss if yr lucky. steep mud, often as not.
tilt that baby about forty or fifty degrees.
stop your whining. With the new Makita 18v lithium hammer drill one can easily make a vertical surface for the bolts. Simply put the drill in "hammer only mode" and chisel a flat surface for the anchor face.
Long anchor bolts work better in poor rock than short ones and some times one can achieve good holding power.
ps. if your rap anchor bolting surface is horizontal you haven't finish the climb.
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