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solo
Apr 9, 2003, 2:34 PM
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I just came across a discussion at
rec.climbing regarding inability of WG (and other big cams) to hold a fall. Have you read it Apollodorus? What do you think about the arguments?
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apollodorus
Apr 9, 2003, 9:14 PM
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I'm not sure I follow the logic of that posting on rec.com. It says that big cams test well in jigs, but they can't hold falls because the "long lever arm can fold the cam at the corner" (axle?). I think he's saying that a testing jig is geometrically perfect, whereas a crack is not, and lateral instability of the cams will cause them to fold sideways.
He goes on to say that he considers ANY cam larger than a #4 Friend to be unsafe to use for pro. I would think that if there were incidents of #5 and #6 Friends (and with #4 and #5 camalots) structurally failing in use, there would be some record of it. That would be pretty big news, and it would be all over the internet. WC and BD would immediately stop selling them, or at least would downgrade the strength ratings. Has anybody ever heard of a big WC or BD cam failing structurally?
In a jig test (which is how all companies test their gear for strength ratings), the aluminum Valley Giant #9 pulls out when the cams bend sideways at about 5000 lb (20 kN). Flared or otherwise awkward placements in rock will be weaker than this, of course. But if the cam is placed properly in good rock, there is no reason to expect it to be tremendously weaker than the test strength.
BTW, that topic on rec.com started out by mentioning specifically that Jeff (Mad Dog) had magnesium Valley Giants. Those are lighter, but weaker than aluminum. And they are NOT intended for use as pro, only for aid or as pusher pieces.
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apollodorus
Apr 10, 2003, 12:33 AM
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I just now named my #16 cam "Wally". Since there is only one, naming it seems right.
The typo in this post gave me the idea. Thanks, Solo.
I am going to do a "real world" test next month. I'll use a reinforced duffel bag filled with 80 kg of rocks, and drop it onto a Valley Giant #9 stuck into a crack. And just like the UIAA rope drop test, I'll do it as a factor 1.8 fall. This will be on a "real" route with a "real" OW crack, falling onto a "real" climbing rope. The only thing that will be fake will be the "climber" taking the whipper.
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passthepitonspete
Apr 10, 2003, 1:10 AM
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I think you'll need a steel basket for the rocks with the kind of force THAT will generate!
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coyoteblues
Apr 10, 2003, 1:17 AM
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Seriously, dude, I think that duffel is gonna blow! Still be fun to hear the results either way.
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philbox
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Apr 10, 2003, 1:45 AM
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When I saw the typo in the title I immediately thought of Dr. pins giant walleye. I thought to myself all sorts of pythonesque thoughts. Lemme see here. The good doctor is carting his giant walleye fish up the offwidths and stuffing these fish into the crack and then falling on them. I guess if you stuffed them in with the scales facing in the right direction they would hold. Now I just gotta figure out how to clip a quickdraw on to it.
...Phil...
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solo
Apr 10, 2003, 6:31 AM
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Sorry for the typo guys. I am not going to edit it, as it proved to be so inspirational for Apollodorus and Philbox. :)
Thanks for the replies.
Solo.
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philbox
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Apr 10, 2003, 6:50 AM
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Oh please no, don`t edit the typo. I love these things dude.
...Phil...
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apollodorus
Apr 10, 2003, 7:13 AM
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I should take bets from you naysayers who doubt my ability to drop 80 kg of rocks in a bag, and not have it blow out. I will use a special bag, not some Jansport bookbag.
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smithclimber
Apr 10, 2003, 5:37 PM
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Hey Tom,
What is the likelyhood that the dropped bag (or it's contents, should the bag explode) will kill someone who happens to be "in the neighborhood"?
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davidji
Apr 10, 2003, 5:57 PM
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In reply to: He goes on to say that he considers ANY cam larger than a #4 Friend to be unsafe to use for pro. I would think that if there were incidents of #5 and #6 Friends (and with #4 and #5 camalots) structurally failing in use, there would be some record of it.
Dingus made the comment about Friends bigger than 4.
In that thread, I asked (& clyde responded):
In reply to: > Would you extend that down to the #6 Friend? Nope, the #5 and #6 Friends are the only large cams I'd trust to leave below my feet.
DMT said:
In reply to: I'd extend it down to a #4 friend. |
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copperhead
Apr 10, 2003, 7:59 PM
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I bet you could get Dr. Piton to drop a full haulbag for you to test the strength of your mighty cams...
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bandycoot
Apr 10, 2003, 8:06 PM
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Hrm, if the bag goes that's going to be one hell of a shotgun spray of rocks... What ARE you going to reinforce the bag with? You definitely have to post the results of the test and maybe bump it a few times to keep it on top so we don't miss it!
Josh
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apollodorus
Apr 10, 2003, 8:17 PM
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The probability of a falling sack of rocks hitting someone who isn't there is zero.
PTPP can't drop a haul bag to test the VG cam, because it's still completely blown out from when he dropped it off Scorched Earth. All the stuff would fall out as soon as it was lifted off the ground.
And the image of gravel blowing out of the bag is not correct. I will NOT be doing the Vertical Limit thing of packing nitroglycerine into the bag. The two or three big rocks will not spontaeously explode, or turn to gravel.
The peak impact force in a UIAA test drop is only about 9 kN, or a bit over 2000 pounds. A bit of webbing, strategically sewn onto the bag, will be more than enough.
And if I can get a digital video cam and editing software together, I'll put an MPEG of the test on my website.
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craterlater
Apr 10, 2003, 10:17 PM
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Smithclimber = Antagonistic jerk.
Niiiiiiiiiiiice. I'm sure Tom NEVER thought about the consequences of the bag failing. Very cool of you to point that out in such a non-condescending way.
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passthepitonspete
Apr 11, 2003, 1:55 AM
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Tom is a class act. This he demonstrated clearly when I dropped his pig! [Ooops] At any rate, I was beating myself up enough for the two of us.
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smithclimber
Apr 11, 2003, 2:35 AM
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In reply to: Smithclimber = Antagonistic jerk. Niiiiiiiiiiiice. I'm sure Tom NEVER thought about the consequences of the bag failing. Very cool of you to point that out in such a non-condescending way.
I never accused Tom of ignoring the consequences at all. I hardly feel that my question was condescending. I merely asked what injury possibilities might be present at the time of the test.
If it wasn't obvious, I was curious about the location he planned on performing the test.
All I did was ask a question and I think if Tom felt I had been condescending or otherwise rude, he would have mentioned it himself or sent me a PM. However, thank you for your concern.
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craterlater
Apr 11, 2003, 3:59 AM
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Yes, Tom is a class act. My guess is that's why he didn't take the bait and get defensive. Me on the other hand...well, I'm a little rough around the edges after a few beers and a couple of Percodans.
In reply to: I hardly feel that my question was condescending.
Really? Care to read it again?
In reply to: Hey Tom, What is the likelyhood that the dropped bag (or it's contents, should the bag explode) will kill someone who happens to be "in the neighborhood"?
Hmm. I wonder how you react when some points out the obvious dangers of your game plan and implies you are being negligent. That's how it actually reads.
In reply to: If it wasn't obvious, I was curious about the location he planned on performing the test.
Nope. It wasn't obvious. It's not what you asked at all.
In reply to: However, thank you for your concern.
Glad I could help.
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timpanogos
Apr 12, 2003, 3:42 AM
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Its kind of funny how our comfort levels seem to get, as well as our prejudices. For example, I wonder how many of the people claming that they would never trust a large cam for a lead fall would place a #13 stopper (or even a #4) and say bomber Id fall on that, heck run it out or what about a #11 wired hex? Anyone would take a lead fall on a solid hex placement right?
#11 hex 10kn
#4 stopper 6kn
#13 stopper 10kn
Dang Tom if those darn giants were only rated for a bit higher than the 20 kn rating in those perfect jig tests, maybe we could trust them for more than body weight aid movements on real rock? Most of your med to larger factory cams rate at 16kn in those perfect jigs, but yea sure, the giants likely lose over 50% of there perfect jig ratings when in real life getting them dangerously close to that 9kn level heck dont worry about re-enforcing the bag the cams sure to go first.
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hans
Apr 12, 2003, 7:52 AM
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:lol:
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