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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Original Post - Oct 23, 2010 - 08:42pm PT
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Picked up some Redhead 1/4" Nail Drive anchors. I didn't realized the body was zinc or I wouldn't have bothered but I had them so I tested one anyway. The zinc sleeve popped in tension (prying) at 620 lbs (2.7 kN). When the sleeve broke, it pulled the nail and loosened the anchor so it fell out without damaging the hole.
I then used the same hole to test a 1/4" stainless wedge anchor that Cragnshag gave me. Seems to be a Hilti. The bolt popped in combined shear and tension at 2450 lbs (10.9 kN).
The hole was hand drilled. Something to do on a rainy Saturday at home.
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mucci
Trad climber
The pitch of Bagalaar above you
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Oct 23, 2010 - 08:57pm PT
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One more reason the zmac rivet is more than ample for a ladder.
What about sheer strength on the nail in?
Thanks for the test.
Mucci
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tomtom
Social climber
Seattle, Wa
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Oct 23, 2010 - 09:06pm PT
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Just a demonstration of Archimedes Principle. Given a long enough lever, you can pull just about anything out.
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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Reply - Oct 23, 2010 - 09:42pm PT
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Actually, I hypothesize that 1/4" steel, split shank, button heads are significantly stronger than the zinc nail nail drive - send me some and we'll see. Look at matweb.com for zinc. The stuff is like butter. They say plain zinc has an ultimate strength of 5370 psi. (Of course I don't know what alloy they might use in anchors) The crappiest steel yields at 36,000 psi.
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mucci
Trad climber
The pitch of Bagalaar above you
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Oct 23, 2010 - 09:52pm PT
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Most certainly the split shafts are stronger in both sheer and pull-out.
I contended that the Z is a good tool of the FA'ist to move quickly through a ladder section. Placing bolts here and there.
As a body weight piece, used only for progression not protection.
Not to mention that pulling them does not ruin the integrity of the hole.
Easy to remove and replace on subsequent ascents.
Thanks for the tests, Now what if I sent you a brand new 1/4 star drive?
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'Pass the Pitons' Pete
Big Wall climber
like Ontario, Canada, eh?
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Oct 23, 2010 - 09:58pm PT
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Wow. I can't believe the quarter-inch stainless expansion bolts are that strong. I thought they failed at around 1200 lbs.
Can you do the same test please on a 1/4" Rawl buttonhead rivet, the kind ASCA supplies us with? I thought those things were good to a couple thousand, and were substantially stronger than the expansion bolt.
At first, this seems counter-intuitive, until you examine the expansion bolt up close, and see that at its narrowest it is rather thinner than a quarter-inch.
Cheers, eh?
Speaking of big-ass levers, Tom used one to test his Valley Giant 9" cam to failure at over 5000 lb, hugely stronger than any commercially made cam.
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Greg Barnes
climber
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Oct 23, 2010 - 10:56pm PT
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Email me your mailing address, I'll send a few 1/4" buttonheads, short and long (1.25" and 1.5"). And maybe a couple of the 1/4" Hilti coil bolts too! Email is greg@safeclimbing.org.
Fun tests!
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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Reply - Oct 24, 2010 - 09:52am PT
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I can do more testing but it does take time. I need to quit hand drilling and get out my old rotohammer. Also, the little green load cell in the photo above is only rated to 2000 lbs. Most load cells are reasonably accurate to 1.5 rated and won't be damaged until 2.0 but it isn't a good idea to go over. I thought the 1/4 SS would break at less than 2000 lbs and once started, it's hard to stop.
I do have a perfect 10,000 lb load cell but it needs a base plate. I can't use it until I can cajole a machinist friend to make one. Basically a 3-3/8" round by 1-1/4" thick with 9 drilled and tapped holes in it.
Greg, check your email.
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Clint Cummins
Trad climber
SF Bay area, CA
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Oct 24, 2010 - 07:23pm PT
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Nice, Dan.
I didn't know there was anything stainless 1/4" that was good, but that 1/4" wedge is pretty strong! Maybe an option for 1/4" aid ladders.
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Mungeclimber
Trad climber
sorry, just posting out loud.
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Oct 24, 2010 - 07:28pm PT
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This is a 1/4" inch in diameter?
nevermind, I guess it is as I look at it longer.
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Strider
Trad climber
one of god's mountain temples.... ಠ_ಠ
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Oct 24, 2010 - 08:09pm PT
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I have a few bolts you can try and break if you like and am more than happy to ship them off.
I have (2) 8mm Fixe rivets. These are the ones that are NOT recommended by Greg B. and I have found they SUCK big time. When you try to drive them into the hole they tend to bend rather than go in. You're welcome to break them though... Need the correct sized drill bit though for the hole...
I have (100) 1/4" split shaft rivets I bought that I would be happy to donate a few. I have a placed more than few of these and never had any problems.
-Nick
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cragnshag
Social climber
san joser
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Oct 27, 2010 - 07:12pm PT
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The 1/4" wedgies are made by Simpson. By the way, they are 316 stainless and very tough- as shown in the results above.
Plenty strong for an aid ladder and perhaps even for pro bolts/ belays on remote slab climbs where you will not be able to generate 2000 lbs on the anchor.
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bwancy1
Trad climber
Here
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Oct 27, 2010 - 08:00pm PT
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Interesting.
You are pointing out the relative "strength" between the two bolts. The fixture appears to be measuring neither shear, nor tension ("prying" as you noted.)
Did you calculate the reported tensile (pullout) strength based on the geometry, etc., or are the numbers that you published simply the force exerted on the fixture at failure?
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Acer
Big Wall climber
AZ
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Oct 27, 2010 - 08:38pm PT
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Always fun times in the shop.
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Captain...or Skully
Big Wall climber
Transporter Room 2
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Oct 27, 2010 - 08:53pm PT
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I can feel the techno-geek AND the Wallclimber attraction to that action.
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Steve Grossman
Trad climber
Seattle, WA
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Oct 27, 2010 - 09:59pm PT
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mucci- Before you get too excited about those zinc anchors remember that the steel cabled rivet hangers are going to wear through the softer body of that sort of anchor faster than a solid steel anchor. It would be interesting to cut into the top half of one down to the steel drivepin to see how that effects the holding power in direct downward shear.
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Mike Bolte
Trad climber
Planet Earth
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Oct 27, 2010 - 10:07pm PT
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interesting, thanks. I don't quite understand your set up from the photos.
tomtom - archimedes' principle is about the buoyancy of a fluid.
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couchmaster
climber
pdx
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Oct 27, 2010 - 10:28pm PT
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Awesome! The mantle of Ed Leeper is falling on your shoulders. Thanks!
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mucci
Trad climber
The pitch of Bagalaar above you
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Oct 27, 2010 - 10:47pm PT
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Steve-
I do agree that a zmac would wear faster than a split shaft buttonhead. However, In regards to the "Traffic" diminishing the sheer strength of a zmac...
Sure after 10 ascents I could see a replacment being needed. Now, If I am on a new route, and place these rivets, I am cutting the drilling time down significantly. That is where they shine, not everthing on a wall needs to be "Protection".
On that same note, it is not the FA's responsibility to outfit the route for the safety of the future teams. If that were true bathooks would be filled with bolts...
Not to mention, getting a repeat of a route in the valley or elswhere is damn near impossible (outside of your friends). No traffic to worry about.
Pretty much the easiest rivet to remove and replace. No one is disputing that.
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Steve Grossman
Trad climber
Seattle, WA
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Oct 27, 2010 - 10:55pm PT
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I am still a stainless machinehead booster. Is a 1/4" hole that is a 1/2" deep really too much work for you?!?
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