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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Reply - Nov 23, 2010 - 11:51am PT
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More 1/4" Button heads, this time a couple 1-1/2" ones. Above, Greg says a 17/64" (0.266") hole and the Fixe web page says 8mm (0.315").
http://www.fixeusa.com/button_head_bolts.htm
Confusion reigns. Perhaps 5/16" (0.313") is the answer. Digging through the drawer of old drills, I found a 17/16" HSS bit and ground it down on the belt sander. Holding it with vice grips, it drilled surprisingly well if kept sharp. However, it tended to get stuck, got dull pretty fast and the tip chipped a little.
First a pullout test, 630 pounds
Then a shear test, I got 1130 lbs which is less than half of the 2715 lbs that I got for the 1-1/4" button head. I think the main thing to remember about button heads is that their capacity is unpredictable and highly dependent on condition of hole, quality of rock, condition of rock face, etc. Most of which you can't assess when installed. In this case, it looks like the rock face spalled when I started loading and the button head bent over at the top of the split where it then tore off. Capacity may differ depending on load direction in relation to the orientation of the split.
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Juan Maderita
Trad climber
San Diego, CA
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Nov 23, 2010 - 11:05pm PT
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Confusion reigns. Yes, and it is difficult to interpret what you might be thinking. Perhaps your confusion is that two diameters of buttonheads are sold on the Fixe website.
FixeUSA sells 1/4" Powers "Drive" (formerly "RawlDrive") buttonheads and also Fixe 8mm buttonheads.
The 1/4" Powers should be drilled with a 1/4" bit. Some people start the hole with a side-to-side slop to oval the entrance of the hole. Place the bolt in the hole with the split in a horizontal position before hammering. This prevents excessive spalling. That seems particularly beneficial with the 8mm and 5/16" buttonheads.
The Fixe 8mm should be drilled with an 8mm bit. 8mm is slightly larger than 5/16". The Fixe buttonhead is particularly soft and likely to bend, more often than not, when driven into a 5/16" hole.
I don't understand why you are messing around with different size bits. Why not just use a rotohammer with SDS bit and be done with it in 15 seconds?
The low numbers you got on the 1/4" x 1.5" are suprisingly low. Something seems off about that. Perhaps the poor result has something to do with the hole being drilled 1/64" too large? Or a problem with the test equipment? Can you repeat the test and get similar results?
I'm also curious if there is a difference in shear strength depending on the orientation of the split. Would you volunteer to shear test one with the split aligned horizonatlly, and another aligned vertically? Not having any empirical data, many of us have placed them with the split on the horizontal, in a slightly oval-entrance hole. Let's see if that's really a good strategy.
Thanks again for your testing work.
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bvb
Social climber
flagstaff arizona
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Nov 23, 2010 - 11:58pm PT
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dude. just solo it.
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Juan Maderita
Trad climber
San Diego, CA
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Nov 24, 2010 - 12:07am PT
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Hey BVB!
How are you? The runouts we did on those short 1/4" bolts down in Baja sure felt like solos!
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BeeHay
Trad climber
San Diego CA
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Nov 24, 2010 - 12:15am PT
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Hey, whatever, this is cool stuff. Thanks for posting.
And, you woke up BVB!
BH
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BeeHay
Trad climber
San Diego CA
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Nov 24, 2010 - 12:17am PT
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BVB only did "walkouts". Dude is way too messed up to run.
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bhilden
Trad climber
Mountain View, CA
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Nov 24, 2010 - 03:13am PT
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My guess why the coil bolt didn't go all the way in is that the coil worked itself far enough up the bolt before the bolt was totally screwed in to enlarge the working diameter of the bolt to be too large to go all the way into the hole.
If you look at the picture of the coil bolt after it has been pulled the coil appears to be all the way up the bolt. One nice things about the wedge bolt is that the sleeve doesn't start working its way down the cone until you tighten it.
Because you are screwing in the coil bolt you are already starting to tighten it. What if you pounded the coil bolt all the way in and then started unscrewing it (if the bolt head starts coming out that could be a problem).
When I think about the coil bolt, how it works and how it is installed it just seems like it is a bad design all the way around.
Bruce
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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Reply - Nov 25, 2010 - 01:36am PT
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Okay, finally got back to this and found my error.
After I broke the original digital readout (see my Nov 11, 2010 posts) popping the 1/4 SS wedge bolt, I dug out another digital readout and went down to the university and calibrated it so that I can use it with two load cells by changing the calibration scale numbers. All I have to do is remember to change the settings - which I didn't. So, in regard to the most recent tests, I calculated the correction factor based on the ratio of the two settings and got 2.96 (3-digit accuracy). I then set up the load cell in series with yet a third load cell, compared the two and got a factor of 3.0 (2 digit accuracy).
I am red faced to admit it but cockpit error occurred. The test gear works fine and the calibrations are good. Now I just wish I could edit the above posted results but don't see how to. Is it possible to edit old posts or even delete the thread and start over?
This does not change any of my results other than the last two, the 1/4 x 1-1/2 button head tests.
The 1/4 x 1-1/2 button head tension test should be 1860 lbs
The 1/4 x 1-1/2 button head shear test should be 3340 lbs
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Salamanizer
Trad climber
The land of Fruits & Nuts!
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Nov 25, 2010 - 01:42am PT
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The 1/4 x 1-1/2 button head tension test should be 1860 lbs
The 1/4 x 1-1/2 button head shear test should be 3340 lbs
Totally BOMBER!
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Mungeclimber
Trad climber
sorry, just posting out loud.
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Nov 25, 2010 - 01:51am PT
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within expected parameters?
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bhilden
Trad climber
Mountain View, CA
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Nov 25, 2010 - 02:24am PT
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What has been pointed out before, the brand new test numbers are interesting, but what is more interesting is the degradation in the numbers over time.
20 years from now, what is the pullout and shear strength of the same bolts? Obviously, environmental factors play a big part in the equation, but I think that is the crux of the issue with respect to 1/4" bolts.
Bruce
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Salamanizer
Trad climber
The land of Fruits & Nuts!
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Nov 25, 2010 - 01:41pm PT
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I've pulled enough old 1/4in bolts to know that 20 years from now they're pull out strengths are a crap shoot at best.
Some are solid as the day they went in, some pull out with your fingers and some snap with little effort. Couple that with the failure rate of the old style Leepers and you're playing Russian Roulette.
When I'm on the sharp end, I could care less about how solid the bolt will be in 20 years, cuz sometimes there won't be a "20 years" if I take too long. And if you think (not that you do, but some do) that you can drill a 3/8" x 2 1/4" bolt even nearly as fast as a 1/4" x 1 1/4" rivet. You my friend would be living in a world of delusions.
1/4 in rivets still serve their purpose, and I'd suspect they will continue to do so for many years to come.
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mucci
Trad climber
The pitch of Bagalaar above you
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Nov 26, 2010 - 12:13am PT
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Fully Bomber.
I have made a full conversion to 1"x 1/4" buttonheads for drilling on lead.
Even got a line on SS hangers for the split shafts...
It's the WAVE OF THE FUTURE!!!
Mucci
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cragnshag
Social climber
san joser
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Nov 26, 2010 - 12:16pm PT
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I like the challenge of placing 3/8" on lead. It requires me to find really good stances... but really I'm just lazy and I don't want to have to return with the tuning forks and drill again.
Of course most routes I climb are on the easier side, so good stances tend to show up when you need them. And I do carry a couple 1/4" buttonheads and a 1/4" bit in the bolt kit "just in case." Problem is I have to plan ahead and switch the bits at a good stance ahead of time since that would be very hard to do (with the Pika anyway) whilst clinging at crappy stance...
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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Reply - Nov 26, 2010 - 01:56pm PT
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Moses is making 1/4 hangers
http://mosesclimbing.com/lightweight-14-bolt-hanger/
I need to get some to test.
I don't really have a problem with 1/4 inch wedge bolts - particularly for backcountry - but I don't like the split shanks. The range of hole size that they will hold in is too small. Remember, for these tests I am drilling perfect holes in perfect rock.
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Juan Maderita
Trad climber
San Diego, CA
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Nov 26, 2010 - 02:16pm PT
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Banquo,
Not following your logic here. Wedge anchors are also dependent on having the proper size hole. Neither type of bolt should be used in anything but hard rock.
1/4" wedge anchors have a thinner coss section due to the threads.
Wedge anchors are not removable. The Powers "Drive" (aka: "split shank") is removable.
I'm not seeing a valid reason for ever using 1/4" wedge anchors.
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cragnshag
Social climber
san joser
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Nov 26, 2010 - 02:41pm PT
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JM,
Not just any 1/4" wedge anchor, but a 316 stainless steel wedge anchor.
Plenty strong (see tests upthread). The alternative light and quick-to-drill anchor is a carbon steel 1/4" buttonhead. Yes it is removable, but who is going to have a tuning fork in the true backcountry? It will get placed and be good for 20 years. Then it becomes a time bomb or simply junk.
This 316 SS 1/4" bolt is not meant to replace 3/8" in the backcountry, just 1/4" non-stainless alternatives where replacement is not likely.
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Juan Maderita
Trad climber
San Diego, CA
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Nov 26, 2010 - 03:58pm PT
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cragnshag,
You make a better case for placing 1/4" wedge anchors under specific circumstances. Perhaps it comes down to one's belief in "replacement is not likely" as a truth. First ascensionists in the backcountry will have to decide the ethical considerations of using a bolt which cannot be removed (except by the extreme method of core drilling with a power drill) for themselves.
What brand of 1/4" 316-SS wedge anchors was tested?
I see different torque specs of 4 and 8 ft-lbs. Let's hope that anyone placing these is quite cautious when torquing. That isn't much torque. It would be really easy to overtorque with one hand, creating a dangerous condition with a stretched and weakened bolt. Many people are unaware that torque specs for stainless are significantly lower than for carbon steel.
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cragnshag
Social climber
san joser
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Nov 27, 2010 - 02:22pm PT
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The tested 316 SS 1/4" are made in Canada by Simpson.
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Slabby D
Trad climber
B'ham WA
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Nov 27, 2010 - 04:49pm PT
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Recently climbed a wall in the Great White North where the first half had been bolted with 1/4" buttonheads and the second half with 1/4" stainless kb3 wedgebolts. The buttonheads were terrifying; heavily rusted, the holes often cratered. The kb3s looked they could have been placed yesterday. Replace-ability is nice and all but there is certainly something to be said for longevity as well. If buttonheads can last 20 years I imagine a stainless wedgebolt can last a Lot longer. 50 years ago I doubt people imagined there would be 36v lithium ion drills that weigh 6 pounds and can drill a big hole in 20 seconds. Lord knows what technology will exist 50 years from now, but I'd bet bolt replacement is going to get a lot easier. From now on I'm going with the 1/4" wedge bolts.
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