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Does anyone out there use Power-Lok AS Bolts?
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By kennoyce
From Layton, UT
Mar 26, 2013
Climbing at the Gallery in Red Rocks
Chad Stebbins wrote:
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.


Yep, the stress bearing area on a 3/8" stud bolt is roughly 5/16", but there are also stress risers due to the threads that further weaken it when compared to a 5/16 rod (like the portion of a 5-piece where the shear load is placed.

Chad Stebbins wrote:
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.


Again, correct. Fortunately, the threaded portion is not loaded in shear, and the bolt is plenty strong in tension (the minimum tensile strength of grade 5 steel is 105 ksi which means that a 1/4" rod will hold over 5000 lbs in tension).

Chad Stebbins wrote:
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...


The 3/8" power bolt (5-piece) uses a 5/16" grade 5 bolt and the 1/2" power bolt uses a 3/8" grade 5 bolt. Stainless power bolts are roughly equivalent in strength to grade 5 steel.

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By Brian in SLC
Mar 26, 2013
Climbing in Smuggler's Notch
Chad Stebbins wrote:
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...


The 3/8" power bolt uses a 5/16" bolt that is grade 5 (with the head stamp on the bolt to reflect that grade). The sleeve is AISI 1010. In stainless, the bolt and sleeve are 304.

In shear, for an impact type load, the sleeve has to help. Also helps that the load isn't on cut threads which might explain the bulk of the strength difference...

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By Chris Vinson
Mar 27, 2013
You don't need to put the sleeve through the bolt hole on a hanger when using a Powerbolt. I want to clarify this. We don't do this with the legacy either.

Also, with a Powers 5 Piece, the washer is redundant and unnecessary, our engineers have signed off on this. The "KNOW YOUR HOLE SIZE" that one manufacturer claims has merit but we found it pointless to use the washer AND put the entire bolt through the hanger's bolt hole. You can use a 1/2" Powerbolt with a 3/8" hanger, toss the washer and put the bolt 3/8" hex head bolt through. Gains in shear are minimal with the sleeve. That bolt is plenty strong if its properly installed.

Tossing the washer enables the cone to have equal threads of engagement when you add the hanger to the system.

Washer Problem
Washer Problem



Metolius makes a similar claim with their hangers also. This shouldn't come as a surprise to most but some people like to argue this point...

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By TBD
Mar 27, 2013
Erik-Pikas wrote:
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.


The photo above reminded me of something. Most climbers do not consider the stainless version of the powerbolt (5 pc) to be economically feasible. So, it is still common practice to use a carbon steel powerbolt with a stainless hanger. What you gain in initial strength with the carbon steel powerbolt may be lost over time due to corrosion issues.

I think it is worth stating that it may be worthwhile to use a stainless steel bolt that is rated at a lower strength, if you are considering using a carbon steel bolt. Consistent performance in the long run is likely more important than rated ultimate strength, especially if "overkill".

The lok-bolt (not AS) seems like a fine option. That said, since you are using 5 3/4 long bolts, the rock quality would probably warrant glue-ins, sounds like you are leaning that way already...

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By MJMobes
From The land of steady habits
Mar 28, 2013
modern man
kennoyce wrote:
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.


thanks kennoyce, you really explained the fact that epoxy may possibly sit in the direct sun and extreme heat for 200-300 days a year and degrade. the truth is nobody here has tested this because it hasnt been around long enough(or 20kn would have responded). Did I make you mad when I pointed out that engineers are not exempt from taking industry bribes?

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By 20 kN
From Hawaii
Mar 29, 2013
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 did not ignore that fact, I am well aware of it. I also well aware that out of the millions of structures that use epoxy, at least some of them have epoxy in exposed areas. I am not sure what you have been installing over the last 20 years, but I can come up with at least a few examples that involved exposed bolts. Many poles and road signs use epoxy-bonded bolts to hold them to the concrete. Guardrails on cliff roads are sometimes grounded via epoxy-bonded anchors. Signs placed amongst the side of bridges in Hawaii are often anchored to the bridge via epoxy-bonded bolts. In short, I do not believe it is something worth worrying about with quality epoxy. Surely the number of bolt failures that come about from developer noobary will infinitely exceed the number of bolts that pull from old epoxy.

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By MJMobes
From The land of steady habits
Mar 29, 2013
modern man
20 kN wrote:
I did not ignore that fact, I am well aware of it. I also well aware that out of the millions of structures that use epoxy, at least some of them have epoxy in exposed areas. I am not sure what you have been installing over the last 20 years, but I can come up with at least a few examples that involved exposed bolts. Many poles and road signs use epoxy-bonded bolts to hold them to the concrete. Guardrails on cliff roads are sometimes grounded via epoxy-bonded anchors. Signs placed amongst the side of bridges in Hawaii are often anchored to the bridge via epoxy-bonded bolts. In short, I do not believe it is something worth worrying about with quality epoxy. Surely the number of bolt failures that come about from developer noobary will infinitely exceed the number of bolts that pull from old epoxy.


I'm installing rebar and threaded rod into bedrock usually, sometimes concrete and sometimes 18" deep. I still have one of those giant 2 tube Simpson guns that collects dust in the basement and a special Hilti gun that some engineer specified I use instead of Simpson (which cost double BTW).
Usually now I use a normal caulk gun with some 2 part Sika or Redhead A7.

Notice your examples are almost all non structural and until recently all would have been done with a cement grout.

I'm talking about the black, south facing rock that bakes even in the winter. If one was to compare the life of glue ins on shady north facing rock and sunny south facing rock I guarantee there would be a difference in lifespan

I'm not talking shit about them at all, I've climbed overhanging routes in Thailand where I was putting my life in the hands of the glue/installer and I'm still here. I've used glue ins on routes over here as well(not overhanging).

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By Stark
From Portland, OR
Mar 29, 2013
In reply to original post, I've used powers lok bolt AS (1/2" x 3.3/4") on lots of routes on southern sandstone definitely use lock tight or some other comparable epoxy on the threads to ensure nut doesn't loosen, I've noticed this on tons of bolts included triplex. This seems to be the only disadvantage in my mind vs. the Powerbolt, which is the gold standard but since I'm pretty much only trying to place stainless these days the powers 5 piece in SS is just too expensive (unless someone else wants to foot the bill). And yes we've whipped all over the Lok bolt, and I tend to log plenty of airtime.
But as the other posters suggested if you are drilling that deep, glue ins are the way to go, they are super easy to mess with, they just take a little extra time to do right (scrubbing the whole with barrel cleaning brush, bevelling the entrance so the welded ring head will sit better, and not really best option for really steep routes much easier on more vertical terrain. Also the glass glue capsules are sweet, but I found the glue cartridges for the caulk gun was the way to go only drawback was having to drill and prep all the holes the first time and glue all the bolts quickly so the $3 a piece tips don't harden)
anyway route developing is one of the greatest joys I've known and I'm super impressed with the level of expertise and thought that many of the posters have expressed. That makes me feel a little safer when traveling to other crags!

One other comment on glueins has any one used chopped sections of SS threaded rod with hangers and nuts. Super cheap, maybe not the most high tech, more redneck engineering...

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By Chris Vinson
Mar 29, 2013
Everything that Stark just posted is spot on. I hesitate to post this on a public forum, but it should be noted.

The reason why a nut will spin and a bolt won't is undocumented with the engineering group at Powers and the pencil pushers we have here. To my knowledge, there has been no conclusive testing done to prove that a nut is more likely to come loose when exposed to cyclical loading. All we have is a "working knowledge" that the nuts will come loose without a dab of locktite or a lock washer. Maybe Jim Titt has some data to reject or confirm this?

Nuts do come loose though, especially in overhung terrain. I wish I had hard data to back this up! So, don't take that last comment as a claim, but a humble suggestion to use Powerbolts in lieu of Power-Loks.

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By Jim Titt
From Germany
Apr 8, 2013
"The reason why a nut will spin and a bolt won't is undocumented with the engineering group at Powers and the pencil pushers we have here. To my knowledge, there has been no conclusive testing done to prove that a nut is more likely to come loose when exposed to cyclical loading. All we have is a "working knowledge" that the nuts will come loose without a dab of locktite or a lock washer. Maybe Jim Titt has some data to reject or confirm this?"

No idea at all, never even thought about it!
But us Euros donīt have any real experience with the multi-piece bolts you use nowadays. The early wave of bolting was done with the infamous "Spit" anchor (made by ITW) which was a common caving anchor in the 70īs and 80īs. These are an internally threaded anchor which is expanded by driving in an internal cone and then a bolt screwed in. They were horribly weak and unreliable (and only 30mm long) so climbers learnt never to trust ANY bolt where you donīt see a nut and threads and the wedge bolt dominates the market.
Since the strength/holding power of the usual wedge bolt we use doesnīt have any connection with how tight the nut is we donīt worry too much about loose hangers, at least until they fall off. In fact there is a school of thought that says if the hanger can move there is less chance of breaking the karabiner if it gets cross-loaded in the hanger itself.

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By MJMobes
From The land of steady habits
Apr 8, 2013
modern man
Stark wrote:
One other comment on glueins has any one used chopped sections of SS threaded rod with hangers and nuts. Super cheap, maybe not the most high tech, more redneck engineering...


I do this on foundations of houses and it seems to be the most economical way to go. I may even go add some 6"long X 1/2" pre-cut pieces to some anchors near me soon. you can buy 3/8 and 1/2 SS threaded rods at any hardware store in 12", 18" and 24" lengths.

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By mattm
From TX
Apr 8, 2013
Grande Grotto
Fall Guy wrote:
I do this on foundations of houses and it seems to be the most economical way to go. I may even go add some 6"long X 1/2" pre-cut pieces to some anchors near me soon. you can buy 3/8 and 1/2 SS threaded rods at any hardware store in 12", 18" and 24" lengths.


Plain ole SS all thread at the Hardware store makes me go "hmm". Pretty hard to determine the quality of that stuff. Could be bottom of the barrel. I'd be especially concerned in 3/8in size.

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By Locker
From Yucca Valley, CA
Apr 8, 2013
...
"In fact there is a school of thought that says if the hanger can move there is less chance of breaking the karabiner if it gets cross-loaded in the hanger itself."


Interesting.

From now on, I'm only placing SPINNERS.

;-)

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