Cobra Anchors -- Reviews?
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The guys I spoke to at Powers indicated that there were no planned changes to be made to the SS PB at this time. |
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I know the 3/8 PS Power Bolt + isn't ideal but it still seems better than the Cobra: |
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Has anyone tried climbtech's legacy bolt? |
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I've tried the legacy bolt, it's a good bolt just expensive and a tad short for the soft sandstone I bolt in. Would probably be more popular if they could get the cost down a bit. |
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I was unable to remove a Legacy bolt from granite, and another was barely removed during testing in hard sandstone. |
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Greg Barnes wrote:I was unable to remove a Legacy bolt from granite, and another was barely removed during testing in hard sandstone. Anyone who intends to use them for an area should first get 10 of them to test removal method in your local stone. I'd strongly recommend that you torque to no more than the minimum mentioned torque with the Legacy bolt, the bolts seem to stretch easily. I see they've changed it from a torque range to a guide torque of 20 ft-lbs, but that's what I used in granite and was unable to remove using their removal guidelines. If I had more to test I would try lower torques, maybe 15 ft-lbs, at least in good granite.Hmmm. That's a bummer Greg given that the premium price was supposedly because of ease of removal. |
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I agree that the Cobra seems pretty substandard in the strength department. |
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Micah Klesick wrote: you can get SS 3/8" x 3.75" Power-Stud wedge bolts for just over $1 each, the same price as a plated Cobra or Powers bolt... and it will last much, much longer, and is stronger...According to Powers, the 3/8" Power-Stud is significantly weaker than the 3/8" Power-Bolt: powers.com/pdfs/mechanical/… For 4000 PSI Normal Weight Concrete: 3/8" x 3.5" Power-Bolt: Ult. Tension: 27.0 kN Ult. Shear: 38.9 kN 3/8" x 3"*,** SS Power-Stud: Ult Tension: 18.7 kN, Ult. Shear: 16.9 kN Perhaps you were referring to a different wedge bolt? If so, please post a link. The Powers "Domestic Wedge Anchor" looks to be a bit stronger than the Power-Stud in 4000psi concrete, but still much weaker than the Power-Bolt, frighteningly so (14.3 kN**) in tension in 2000psi conrete, which is comparable to soft rocks like volcanic stone and some sandstone: powers.com/pdfs/mechanical/… Unfortunately it seems to me that wedge bolts are doomed to be weaker than Power-Bolts at any given diameter due to the threaded shaft. I've yet to find a 3/8" diameter wedge bolt that meets the UIAA standard**, but I'd love to be proven wrong. (*3" is the longest 3/8" Power-Stud for which Powers provides data) (**the UIAA standard is 20 kN "axial load bearing capacity", aka tension, and 25 kN shear) |
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Correct. Stud's are always going to be weaker than the comparable Powers 5-pieces, however in the rock we have around here (very hard basalt) they are more than adequate (4,200lb pull/3,760lb shear). I would never use wedge bolts for sandstone, or tuff, such as at Smith Rocks. There I would only use 5-piece bolts, or glue-ins. But in the basalt we have around here, they work well. I was looking it up a while back, supposedly the basalt here in the area runs between 12,000 and 20,000 psi, so it is quite hard, on par with good granite. |
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Monomaniac wrote: Unfortunately it seems to me that wedge bolts are doomed to be weaker than Power-Bolts at any given diameter due to the threaded shaft. I've yet to find a 3/8" diameter wedge bolt that meets the UIAA standard**, but I'd love to be proven wrong. (*3" is the longest 3/8" Power-Stud for which Powers provides data) (**the UIAA standard is 20 kN "axial load bearing capacity", aka tension, and 25 kN shear)Hilti KB3s meet UIAA specs and are my favorite stud by far. The clip is much better than other designs and has more consistent lock up with fewer turns in my experience (Hard Limestone). Also available in both 304 and 316. 3/8 x 3 3/4" 304SS ~ $2.75ea ebay will also occasionally have them. 3/8" KB3 specs |
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Micah Klesick wrote:...in the rock we have around here (very hard basalt) they are more than adequate (4,200lb pull/3,760lb shear)...I'm not so sure. 3,760 lb is 16.7kN. The UIAA standard is 25 kN for shear. I agree rock strength is a big factor in pull-out strength but not so much for shear. |
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mattm wrote: Hilti KB3s meet UIAA specs and are my favorite stud by far. The clip is much better than other designs and has more consistent lock up with fewer turns in my experience (Hard Limestone). Also available in both 304 and 316. 3/8 x 3 3/4" 304SS ~ $2.75ea ebay will also occasionally have them.Wow, those are quite strong for a 3/8" diameter wedge bolt. Still not as strong as a power bolt in shear at 3000psi and above, but they meet the UIAA standard. Where are you getting that price? The best I can find is $4.12 from Climbtech. |
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Monomaniac wrote: I'm not so sure. 3,760 lb is 16.7kN. The UIAA standard is 25 kN for shear. I agree rock strength is a big factor in pull-out strength but not so much for shear.Mono, do you not like the KB3 for some reason other than the stud sticking out a little bit? Because as Matt notes above, they certainly meet UIAA standards, they set super easy (I've never had one spin on me...though I am diligent about cleaning my holes), and even the SS rigs are pretty cheap. Moreover as I think someone pointed out, they don't stick out nearly as bad as some other, perhaps older, models of studs. EDIT: Your post above went up while I was posting....so you pretty much answered my question. To answer your question about price, I am not sure where Matt is getting them, but the friend that I always bought from gave them to me for ~$2.50/bolt, so that kind of deal must exist somewhere (though he bought by the thousand). But even rapbolting.com has them for $3.29/bolt if you buy a box of 50. |
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That first post, quoting Micah, was referring to his recommendation of the Powers "Power-Stud". |
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I'll ditto the KBIII's as nice studs. I place them as the first three off the ground, and, at cruxes and anchors. |
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In general with regards to the quality of bolt installs I believe knowledge, experience and execution especially with respect to detail are critical. Whether it's an adhesive or mechanical bolt installs can be botched in a plethora of ways.
Having also placed glue ins they have their pros and cons. The upside being greater chemical resistance (i.e., rust), holding power, increased life span, stress free and lower visibility. The downside is price, cure time and lack of original hole reuse. |
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Joseph Crotty wrote:Having also placed glue ins they have their pros and cons. The upside being greater chemical resistance (i.e., rust), holding power, increased life span, stress free and lower visibility. The downside is price, cure time and lack of original hole reuse.Honestly, the only real downside to Glue Ins is the extra work, both placing and, eventually, replacing. Price - Wave's in 304SS are $6.25 Bolt Products equivalent in 316SS are $3.50 (shipping is the challenge right now... group buy anyone? I've heard of people bringing Jim's stuff back in suitcases!) Cure Time - Can be 30min with certain glues. By the time I finishing cleaning up a newly-bolted route it's ready to climb. Hole Reuse - Won't be needed that often but can be cored out if needed (agreed it's a PITA) |
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First, The new Powers PB+ 3/8 diameter bolts should not be used for climbing. |
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Thanks to a community funded fixed gear initiative in Red River Gorge (humid environment) nearly all developers bolting new routes on public land are now using SS powerbolts or glue ins. The model is that developers pay the equivalent of a carbon steel PB and the community fund makes up the difference to buy the SS equivalent. Because we are placing bulk orders together we can get the hardware cheaper than buying them individually. Some of the funds from the Iniative also go towards rebolting efforts using glue-ins. The iniative should greatly reduces the burden on future rebolting needs. Perhaps this model could work for other areas? |
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" I use the the plated Cobra 1/2" bolts frequently (3.5) in arid environments and find them to be more than adequate. I just want to point out that 1/2 Cobra bolts (which are plenty strong) are still substantially less expensive than any of the 3/8 hardware by most of the companies listed in this thread."
----------------------------- Kevin, I assume you are bolting somewhere around SLC? I'd be interested in some anecdotal results regarding aging on the hardware you placed which is now 10 years old or older. I'd like some feedback on any problems unique to placing Cobras. For instance do the threads clog during installation? I may have placed around 300 to 400 Rawl bolts and know how they feel during tightening. Are the Cobras any different in your experience? For myself I am placing in limestone, quart monzonite, basalt and Red Rocks sandstone. I have pulled a couple bolts which were 10 years old or older. Even in limestone in this climate, if the area receives little water run off, after 10 years there is very minimal pitting. 3/8" Rawl Bolt placed over 10 years ago in granite at Keyhole Canyon, NV Apologies for the thread drift. I understand about the need for stainless and try to bolt responsibly. I thought I was going to get the last of the local Fasco Powers plated stock yesterday but there was some misunderstanding and Fasco is out of the old style Powers bolts. I am looking on the internet but with little hope. It seems for my use I am either buying the plated 1/2" Cobra bolts or buying the new version 1/2" Power Bolt+. I am interested in what length Cobra bolts you are using and in what rock or conditions. I am especially interested in your experiences if you are developing around the Cottonwood Canyon areas. I have a multi-pitch line I want to do in California in an environment similar to LCC and wonder about whether I should use stainless for all of it or part of it. |