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Does anyone out there use Power-Lok AS Bolts?
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By Erik-Pikas
From Upstate NY, will travel
Mar 21, 2013
Self portrait, Mt Rainier via the Kautz Ice Field.

Powers Fasteners makes several bolts which may be appropriate for climbing applications. Many climbers are familiar with "Power Bolts" (the removable bolts.) I'd like to know if anyone out there has first hand knowledge about using the Power-Lok AS bolts. (the non-removable model.) Specifically the 1/2" diameter bolts. I personally have been using removable Power Bolts (1/2' dia.) on many routes, but the Power-Lok bolts are a fraction of the price. They have the disadvantage of not being removable, which I suppose is a consideration if you want to inspect the bolt in the future. The Powers Fasteners website lists the ultimate shear strength as 19.0kn when placed at a depth of 2.5". That is as opposed to 30.8kn for the Power Bolts at the same depth. (ultimate load capacities in 2000psi concrete). It is worth noting that around here we have compact sandstone and have been using the 5.75" X1/2" Bolts. Powers does not list the failure strength of the Power-Lok bolts at depths of greater than 2.5", although in general the longer a bolt is the greater its strength due to the way the rock crumbles when a bolt fails. It is easy to say "just use the stronger bolts and never worry" but there is such a thing as overkill, and at three times the price it is worth questioning whether the overkill makes any practical difference. Please post comments and feedback. Please don't turn this into a discussion about glue ins versus expansion bolts, that's a subject for a different thread. Thanks!


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By John Wilder
From Las Vegas, NV
Mar 21, 2013

In general, stud bolts are cheaper, so many route developers prefer to use them.

The downside, of course, is replacement. To replace, folks will have to use a breaker bar to snap the bolt flush with the rock (assuming it doesnt spin, in which case you'll have to take a grinder to it), which usually makes it harder to patch.

I'll leave it to east coast folks to talk about whether stud bolts are appropriate for your rock.


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By kennoyce
From Layton, UT
Mar 21, 2013
Climbing at the Gallery in Red Rocks

John Wilder wrote:
In general, stud bolts are cheaper, so many route developers prefer to use them. The downside, of course, is replacement. To replace, folks will have to use a breaker bar to snap the bolt flush with the rock (assuming it doesnt spin, in which case you'll have to take a grinder to it), which usually makes it harder to patch. I'll leave it to east coast folks to talk about whether stud bolts are appropriate for your rock.


The power-lock is not a stud bolt (that would be the power-stud), but is a sleve bolt with a hex nut instead of a hex-head bolt. I don't know why the OP stated that they are not removeable since the sleve bolts like this that I have removed are much easier to remove than a power bolt is. Generally these just aren't used because they are so much weaker than a power-bolt.

Also, if a developer using stud bolts does it correctly and overdrills the hole, all you have to do to replace a stud bolt is tap it back into the rock until it is burried, then patch over it.


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By TBD
Mar 21, 2013

I am also curious what the bolt experts would say on this. I have often heard that these types of sleeve anchors are not suitable for climbing protection, but have not heard a sufficient explanation.

These bolts in 1/2 inch should perform similarly as a 3/8 power stud, if using a 3/8 inch hanger. A 1/2 inch hanger should give you additional shear strength. The sleeve should give an advantage over a wedge design in softer rock.

Compared to a powerbolt, the negatives to this bolt are that they are slightly weaker because the shaft is threaded along its entire length and the bolt is more likely to fail if the nut becomes loose. Some thread lock or a ny-lock nut should address the latter issue.

Practically speaking, I don't see a significant difference in this design compared to the fixe triplex or climbtech legacy bolt.


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By J. Albers
From Colorado
Mar 21, 2013
Bucky

kennoyce wrote:
Also, if a developer using stud bolts does it correctly and overdrills the hole, all you have to do to replace a stud bolt is tap it back into the rock until it is burried, then patch over it.


Yeah, I always thought that this was common knowledge, but considering this statement:

John Wilder wrote:
To replace, folks will have to use a breaker bar to snap the bolt flush with the rock (assuming it doesnt spin, in which case you'll have to take a grinder to it), which usually makes it harder to patch.


perhaps over drilling is not common knowledge?


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By kennoyce
From Layton, UT
Mar 21, 2013
Climbing at the Gallery in Red Rocks

Chad Stebbins wrote:
I am also curious what the bolt experts would say on this. I have often heard that these types of sleeve anchors are not suitable for climbing protection, but have not heard a sufficient explanation...... Practically speaking, I don't see a significant difference in this design compared to the fixe triplex or climbtech legacy bolt.


These are similar to a fixe triplex, but look closer at the climbtech legacy bolt and you'll see that it is more like a power-bolt. I'm not sure why, but if you look at the specs on the powers website, the pull-out strength of these bolts (1/2") is only 10.7 kN and that's in 3500 psi concrete. That is the reason I'd never use them. It's not that they wouldn't hold most falls, but at that low of a strength, fatigue and other factors start to come into play.


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By TBD
Mar 21, 2013

kennoyce wrote:
but look closer at the climbtech legacy bolt and you'll see that it is more like a power-bolt.


oops, my bad

kennoyce wrote:
I'm not sure why, but if you look at the specs on the powers website, the pull-out strength of these bolts (1/2") is only 10.7 kN and that's in 3500 psi concrete.


I hear you, but the minimum embedment depth in lok-bolt specs is 1.5 inches. Hard to compare to the power bolt 1/2 spec, since it shows 2.5 embedment, and different strength concrete for that matter.

Another issue with relying on these specs is that rock usually has a higher compressive strength than concrete


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By Erik-Pikas
From Upstate NY, will travel
Mar 22, 2013
Self portrait, Mt Rainier via the Kautz Ice Field.

Hi Guys, Thanks for all the feedback. I know the hex nuts (and thus bolt hangers) are easy to remove on the Power-Loks, but as far as I can tell the bolt itself is not meant to be removed. Obviously it can be pushed back into the rock, but that doesn't allow for inspection.
What I did not previously know was that the reason the shear strength is weaker is due to the threading all the way up the length of the bolt on the Power-Loks. BTW, on the Powers website there are specs for the Power-Lok bolts, and Power-Lok AS. the AS model is stronger and has more detailed specs listed. It sounds like the consensus is to stick with the Power bolts despite the higher price. I'd feel bad if someone got hurt because a bolt that I placed broke.


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By kennoyce
From Layton, UT
Mar 22, 2013
Climbing at the Gallery in Red Rocks

Erik-Pikas wrote:
Hi Guys, Thanks for all the feedback. I know the hex nuts (and thus bolt hangers) are easy to remove on the Power-Loks, but as far as I can tell the bolt itself is not meant to be removed. Obviously it can be pushed back into the rock, but that doesn't allow for inspection...


Nope, the whole bolt can be removed pretty easily. All you have to do is take off the nut, washer, and hanger, then you just grab the sleve portion of the bolt with a pair of needle nose pliers or something similar, give it a tug and the whole bolt will pull right out. These are pretty much the easiest bolts to remove beside the fixe triplex.


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By M Sprague
Administrator
From New England
Mar 22, 2013
Lichen head. Me, with my usual weatherbeaten, lichen covered look from scrubbing a new route.

It doesn't solve the problem of being easily removable, but with sandstone, if you are really sure about your placements, I would go with glue-ins, probably the SS Fixe. I use the 1/2" Rawl Powers bolts for granite, but yeah,they are getting crazy expensive, so I have been thinking of going to the glue-ins even for that stone. I have been using Fixe 3/8" SS wedge bolts lately for slabbier routes, but I don't really like wedge bolts with nuts and exposed threads.

Those Power Locks seem weaker than I would want to use. I like big overkill.


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By 20 kN
From Hawaii
Mar 22, 2013

Erik-Pikas wrote:
Powers Fasteners makes several bolts which may be appropriate for climbing applications. Many climbers are familiar with "Power Bolts" (the removable bolts.) I'd like to know if anyone out there has first hand knowledge about using the Power-Lok AS bolts. (the non-removable model.) Specifically the 1/2" diameter bolts. I personally have been using removable Power Bolts (1/2' dia.) on many routes, but the Power-Lok bolts are a fraction of the price. They have the disadvantage of not being removable, which I suppose is a consideration if you want to inspect the bolt in the future. The Powers Fasteners website lists the ultimate shear strength as 19.0kn when placed at a depth of 2.5". That is as opposed to 30.8kn for the Power Bolts at the same depth. (ultimate load capacities in 2000psi concrete). It is worth noting that around here we have compact sandstone and have been using the 5.75" X1/2" Bolts. Powers does not list the failure strength of the Power-Lok bolts at depths of greater than 2.5", although in general the longer a bolt is the greater its strength due to the way the rock crumbles when a bolt fails. It is easy to say "just use the stronger bolts and never worry" but there is such a thing as overkill, and at three times the price it is worth questioning whether the overkill makes any practical difference. Please post comments and feedback. Please don't turn this into a discussion about glue ins versus expansion bolts, that's a subject for a different thread. Thanks!



You titled your thread in reference to the Power-Lok AS bolt, but your post's text references the Power-Lok. I assume you are referring to the standard Power-Lok? Anyway, the 1/2" Lok-Bolt is "okay," but the Power-Bolt is superior.

Regarding your statement about the 19kN strength rating, the bolt is listed at 19kN for 2000, 4000 and 6000 PSI concrete. That implies the failure strength of the bolt is 19kN, and choosing a longer bolt wont change anything. If the rock was breaking out at the 2,000 PSI test, increasing the compressive strength would yield a greater pull out strength, but that is not happening according to Power's data. Thus, the data seems to indicate the bolt breaks clean off at 19kN, which if true, it does not meet the UIAA's requirements.

Now, if you are referencing the Power-Lok AS then hell no they are not suitable, not even in the 1/2" version. The 1/2" version does not come remotely close to meeting the UIAA 123 bolt requirement spec.


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By Old and Busted
From Centennial, CO
Mar 23, 2013
Stabby

M Sprague wrote:
but I don't really like wedge bolts with nuts and exposed threads.

That's funny b/c I personally don't like the cap bolts you get with the 5 piece. You have to pretty much rely on faith those things are both made to and installed to specifications. I've torn the top off of those a few times.


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By Chris Vinson
Mar 25, 2013

Mike Lane wrote:
That's funny b/c I personally don't like the cap bolts you get with the 5 piece. You have to pretty much rely on faith those things are both made to and installed to specifications. I've torn the top off of those a few times.


Mike, can you elaborate a little bit on this? Plated or stainless bolt?

There is "faith" to some degree with all bolt placements that the installer is competent. That was an interesting post though.


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By Old and Busted
From Centennial, CO
Mar 25, 2013
Stabby

Its the cap. You can't see underneath it. Even with the 1% of bolts installed with a torque wrench, they are rarely calibrated right. I'm a mechanical contractor and have either personally set or supervised the installation of 10's of thousands of bolts through the years. so when we get into rock bolts and usually have no idea who set the thing, it can get a little sketch. Hence my preference for seeing a bit of stud and a nut over a cap bolt. But it's nothing more than a personal preference.
I like Sprague using 1/2" 's, you then have a 3/8" stud. A 3/8" 5-pc. is only a 5/16" stud.


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By Chris Vinson
Mar 25, 2013

Ah, I see what you mean. A lot of caver's share your thoughts, sometimes seeing the threads its a nice way to assure that it was properly installed. There are pros and cons to every bolt.

I'm not sure if you have seen them, but definitely give the Hilti HSL with the torque cap a look, specifically the bolt in the middle on this link.

Hilti HSL

That red torque cap has three aluminum rods in it that break away from the bolt head once the proper torque has been reached. The red cap pops off essentially. It helps to ensure proper torquing (not to imply proper installation but its a BIG step in the right direction) if you have any doubts.

Just a thought.

Sorry if this might be getting a bit off topic, sorry about that Erik-Pikas!


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By Erik-Pikas
From Upstate NY, will travel
Mar 25, 2013
Self portrait, Mt Rainier via the Kautz Ice Field.

Not a problem. You guys from Climbtech are awesome. I'm really happy to see that a lot of knowledgeable people have responded to my question. I was hoping someone was going to say "oh yeah, we've been using the Power-Lok As bolts for years and never had a problem! Save your money and use 'em!" But I'm definitely not hearing that.

Now, regarding glue-ins, from what I've read elsewhere, I'm convinced that they are much better than expansion bolts, at least in soft rock. I have just personally never placed them, and I have been reluctant to learn the hard way. So, if any of you have been refraining from posting insights or words of wisdom regarding glue ins, I open the floor to you...


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By 20 kN
From Hawaii
Mar 25, 2013

Erik-Pikas wrote:
So, if any of you have been refraining from posting insights or words of wisdom regarding glue ins, I open the floor to you...

Glue-ins are far superior, but they can be more expensive and they require additional training and knowledge to place correctly. If you place glue-ins, use stainless steel bolts as glue-ins cannot be removed (easily).


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By MJMobes
From The land of steady habits
Mar 25, 2013
modern man

20 kN wrote:
Glue-ins are far superior, but they can be more expensive and they require additional training and knowledge to place correctly. If you place glue-ins, use stainless steel bolts as glue-ins cannot be removed (easily).


glue ins are a pain in the ass and I'm glad someone finally said that a 3/8" 5 piece is basically a 1/4"er which we have been trying to get rid of for years.

once the glue ins have been around baking in the sun for 10-20 years we can say they are superior, for now I would not say that.

has anyone tested the life of the glue over time yet?


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By TBD
Mar 25, 2013

Not to drift back to the original topic but...

20 kN wrote:
Thus, the data seems to indicate the bolt breaks clean off at 19kN, which if true, it does not meet the UIAA's requirements.


I find this interesting. For many years, standard practice has included using 3/8 wedge bolts. The specs for the power-stud indicate that these bolts break in tension at 18.7 kN and 16.9 kN in shear. The 1/2 inch lok bolt (not AS) performs better than this in both modes.

While this may not meet UIAA's requirements, it likely exceeds what is in place on tens of thousands of climbs around the country. In practice and the limited discussion in this thread, these should be fine in climbing applications. Unless there is some other issue with these bolts???


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By TBD
Mar 26, 2013

20 kN wrote:
Now, if you are referencing the Power-Lok AS then hell no they are not suitable, not even in the 1/2" version. The 1/2" version does not come remotely close to meeting the UIAA 123 bolt requirement spec.


The shear exceeds 20kN. Hard to compare in tension, the minimum embedment stated is 1.5 inches. I think it is hard to say without more info...


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By 20 kN
From Hawaii
Mar 26, 2013

Chad Stebbins wrote:
Not to drift back to the original topic but... I find this interesting. For many years, standard practice has included using 3/8 wedge bolts. The specs for the power-stud indicate that these bolts break in tension at 18.7 kN and 16.9 kN in shear. The 1/2 inch lok bolt (not AS) performs better than this in both modes. While this may not meet UIAA's requirements, it likely exceeds what is in place on tens of thousands of climbs around the country. In practice and the limited discussion in this thread, these should be fine in climbing applications. Unless there is some other issue with these bolts???
The Power-Stud bolt is not the best bolt on the market. The Hilti KWIK III 3/8" 304 stainless steel bolt meets the UIAA's strength requirements. Regardless, I never said the 1/2" Lok-Bolt is not suitable for climbing, it is fine. I just said there are better options. Either way, I would rather clip a 1/2" Lok-Bolt than many of the alternatives some developers use.

As far as the epoxy lifespan goes, that really depends on what epoxy you use. However, epoxies have been around for a reasonable amount of time. They are used to hold buildings and highway panels together. I suspect most new buildings are partly assembled with epoxy-bonded rebar. As long as a developer uses quality epoxy, she or he could expect lifespan in excess of the lifespan of the route or the bolt. It is hard for me to quote an exact number as I dont really know, but if I had to guess I would say 50 - 100 years is a reasonable value. Remember, this stuff is used in industrial applications. I am sure the engineers accounted for the lifespan of the epoxy when they choose to use it in the manufacturer of 100-story buildings that they expect to last a century. :)


Fall Guy wrote:
glue ins are a pain in the ass and I'm glad someone finally said that a 3/8" 5 piece is basically a 1/4"er which we have been trying to get rid of for years. once the glue ins have been around baking in the sun for 10-20 years we can say they are superior, for now I would not say that. has anyone tested the life of the glue over time yet?

They are a pain in the ass no doubt. But they are the most secure option available. Glue-ins have more advantages than just lifespan. Glue-ins are also safer in soft rock. Expansion bolts are more likely to pull than glue-in bolts when placed in crappy sandstone or heavily pocketed and porous rock.

I am not sure why you believe a 3/8" Power-Bolt is analogous of a 1/4" bolt. That is not even remotely true. The Power-Bolt is one of the strongest expansion bolt models on the market. The 3/8" Power-Bolt is stronger in tension and shear than the 3/8" Power-Stud wedge bolt. In fact, the 3/8" Power-Bolt is nearly as strong as some 1/2" wedge bolts.

Chad Stebbins wrote:
The shear exceeds 20kN. Hard to compare in tension, the minimum embedment stated is 1.5 inches. I think it is hard to say without more info...


I agree it is hard to say without more info. But for now all we know is that the bolt is only rated for 10kN in tension.


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By NorCalNomad
From San Francisco
Mar 26, 2013

Nice to be in CA were most of the time you just have to sink a nice 3/8 SS bolt into granite and be good to go :P


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By MJMobes
From The land of steady habits
Mar 26, 2013
modern man

20 kN wrote:
As far as the epoxy lifespan goes, that really depends on what epoxy you use. However, epoxies have been around for a reasonable amount of time. They are used to hold buildings and highway panels together. I suspect most new buildings are partly assembled with epoxy-bonded rebar. As long as a developer uses quality epoxy, she or he could expect lifespan in excess of the lifespan of the route or the bolt. It is hard for me to quote an exact number as I dont really know, but if I had to guess I would say 50 - 100 years is a reasonable value. Remember, this stuff is used in industrial applications. I am sure the engineers accounted for the lifespan of the epoxy when they choose to use it in the manufacturer of 100-story buildings that they expect to last a century. :) They are a pain in the ass no doubt. But they are the most secure option available. Glue-ins have more advantages than just lifespan.


You ignored the fact that in most applications the epoxy is buried in concrete where it never sees the sun and we all know the sun damages quite a few things. I think you put too much trust in engineers, they get kickbacks for promoting new products almost as much as doctors do with pharmaceuticals. I've been using epoxy in concrete/brick/stone for about 20 years at work and I can say that not once was the end result exposed to the elements. At least with the glue in bolts you can visually inspect the glue and even scrape away at it a bit to see if its degrading. I'll be keeping a close eye on the latest cliff I have been using glue ins on, its south facing and gets hot there even in the winter so those things are going to BAKE in the summers.

It must be the layman in me that cant understand how a 3/8" 5pc could have more shear strength then a 3/8" wedge. Does the sleeve somehow absorb impact???


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By Old and Busted
From Centennial, CO
Mar 26, 2013
Stabby

A 5 pc. is @ 5000 lbs.*, a 3/8" Hilti KB is @ 4000. But then Red Heads which suck rate higher than Hilti too. I still favor Hilti's myself.


  • - give or take, depending on the concrete strength.


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By kennoyce
From Layton, UT
Mar 26, 2013
Climbing at the Gallery in Red Rocks

Fall Guy wrote:
You ignored the fact that in most applications the epoxy is buried in concrete where it never sees the sun and we all know the sun damages quite a few things. I think you put too much trust in engineers, they get kickbacks for promoting new products almost as much as doctors do with pharmaceuticals. I've been using epoxy in concrete/brick/stone for about 20 years at work and I can say that not once was the end result exposed to the elements. At least with the glue in bolts you can visually inspect the glue and even scrape away at it a bit to see if its degrading. I'll be keeping a close eye on the latest cliff I have been using glue ins on, its south facing and gets hot there even in the winter so those things are going to BAKE in the summers.


Now this is just funny, you do realize that the only portion of the epoxy that is exposed to the elements is the outer surface right? That means that like 99% of the epoxy on a bolt is burried and never sees the sun/elements. You are right that the very outer surface of the epoxy will degrade due to the sun exposure, but it will never degrade to the point of compromising the bolt (at least due to exposure). As far as your comments about engineers go, all I can say is that it's pretty obvious that you're not an engineer.


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By TBD
Mar 26, 2013

Fall Guy wrote:
It must be the layman in me that cant understand how a 3/8" 5pc could have more shear strength then a 3/8" wedge. Does the sleeve somehow absorb impact???


The threads on a wedge bolt reduce the actual diameter. The outside of the threads measure 3/8, measuring at the bottom of the thread groove would produce something less.

The sleeve on a 5 piece would add strength in shear, in tension it would not. A 3/8 5 piece has a 5/16 bolt in the sleeve. At the cone the threads reduce this diameter. You may not be that far off saying that the lowest diameter portion of the bolt resisting tension force is 1/4 inch.

I believe the power bolt is made from fairly high grade steel. I recall that the inner bolt on a 5/16 power bolt is grade 8, where the larger diameters are grade 5, this could explain the high performance. It's been awhile, so I could be wrong...


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