Broken bolt in Owens - 5/16" buttonhead

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bhilden

Trad climber

Mountain View, CA/Boulder, CO

Mar 20, 2015 - 05:34pm PT

Dimes,

the anchor bolts from Walk on the Steep Side look to be Rawl 'Drop-in' bolts.

http://www.powers.com/product_06308.php

With this type of bolt there is an internal pin in the sleeve. As you tighten the bolt into the sleeve you push the pin further down the sleeve which causes the end of the sleeve deepest into the rock to expand.

There are a couple of negatives with this type of bolt. First, you have to drill a 1/2" hole to be able to use a 3/8" bolt.

Secondly, if you can't tighten the bolt all the way down into the sleeve (I have seen this happen in Pinnacles National Park) you either have a spinner or you have to cut off the end of the bolt. The bolts in the photo from Walk on the Steep Side are quite short compared to what I have seen that normally come with that bolt. Too short of a bolt and you might not get enough expansion which would reduce the pull-out strength of the bolt.

Lastly, they don't come in stainless steel.

ps- thanks for all your hard work replacing bolts!

Juan Maderita

Trad climber

"OBcean" San Diego, CA

Mar 20, 2015 - 06:18pm PT

bhilden,
That style of drop-in anchor does not receive it's expansion from the bolt being tightened. A setting tool is used with repeated (20ish) hammer blows to drive a small internal cone toward the base of the anchor. The cone is what you referred to as the "pin."
In the 3/8" size (requires 1/2" drilled hole), there is 5/8" of female thread to accept a cap screw (bolt). Thus, the short bolt pictured by "Dimes".

There are other strong drop-in anchors, such as the "Saber Tooth" which are driven down onto a partially external cone. Precise hole depth is required.

Then there are some weaker anchors such as, the Powers "Single" and "Double." Those are expanded when a bolt is screwed into them. IMHO, none of these should be used for climbing purposes, and certainly not the "Single" or "Double."

bhilden

Trad climber

Mountain View, CA/Boulder, CO

Mar 20, 2015 - 06:38pm PT

^^^^^^
Juan,

you are correct. I think one of the reasons why we have had problems with these in the Pinnacles National Park is that the users just assumed that screwing in the bolt would set the cone/pin. When that failed, the climbers just cut off the end of the bolt so that the hanger was flush.

MisterE

Gym climber

Bishop, CA

Mar 20, 2015 - 08:38pm PT

Thanks, Dimes - those shallow screw-expansion ones are skeeeetchy.

ionlyski

Trad climber

Kalispell, Montana

Mar 20, 2015 - 08:46pm PT

Yeah, but the length of that bolt that screws into the drop in anchor is not short. It uses the threads for strength and it only takes so many threads to make good contact.

Drop ins haven't been real popular for climbing applications for reasons I'm not sure but I've used them for other applications.

Arne

ryankelly

Trad climber

Bhumi

Mar 20, 2015 - 11:19pm PT

Bolts will fail and so will our judgement from time to time.

Much love and respect to Scott Sederstrom.

Thanks ,Dan McD for investigating

rockgeir

Trad climber

Tucson, AZ

Mar 21, 2015 - 02:42pm PT

Greg,

Earlier in this thread you asked about known 3/8" split shaft failures. We recently had one in Cochise on Be All, End All. There is a post on MP about it.

Also, I recently broke one of these on Devoid in Cochise while replacing it. The bolt failed with almost no force applied to the bolt puller. Others I have pulled have been quite solid.

There are a lot of 5/16" and 3/8" split shafts in Cochise; I and others are working on replacing them as we are able.

msiddens

Trad climber

Mar 22, 2015 - 08:29am PT

Thanks for sharing this

two-shoes

Trad climber

Auberry, CA

Mar 22, 2015 - 01:28pm PT

I've been reading this topic about 5/16" Rawl-Drive button head compaction bolts, and I think I have a few things of interest to throw into the mix.

There has already been a lot of valuable discussion. What Sam Lightner Jr. had to offer about the subject of corrosion is something that I've long been mindful of. I like what Greg Barnes, and Bruce Hildenbrand, as well as others, had to offer on the subject as well. A lot of us here have been driving bolts, and removing bolts for decades, and we have, as a collective, many, many cumulative years of in-the -field knowledge on this subject.

Here is what I can add to the mix, in a nutshell: A way to remove 5/16" button heads. A good reason for their removal, and the removal of all ferrous metal bolts, or ferrous metal hangers.

I don't know if Ed Leeper is still around. If he is, he certainly could throw in some valuable info into this mix. So could Jeff Achey who wrote in Climbing Magazine just last year, I believe, the single best article that I have every seen written on the subject of bolts and corrosion. http://www.climbing.com/climber/built-to-last/

I've had a means of driving a modified, rather straight bladed, Stanley brand claw hammer underneath bolt hangers, and bolts, that I had first used in about 1987. The modification is a widened slot that will allow 5/16" button heads to be fairly easily pulled. I've pulled a few hundred bolts through the years with this system, mostly 1/4" of course. But this tool can be driven under 5/16" button heads with just a little bit more effort. Of course, one needs the aid of another hammer for the driving. The claw hammer needs to be driven under the hanger. This is often best along the axis at the bottom of the hanger. Then the angle of the driving hammer is changed by hammering on the bottom edge of the hammer face of the claw hammer. This has a levering force that will lever the bolt out in just a few blows. You need a straight blade claw - a curved one will not work.

The primary reason that causes all ferrous metal, case hardened bolts, hangers, and pitons to readily corrode and weaken is stress. If any hardened ferrous metal or ferrous alloy is put in a stress position, over time, stress fractures will occur. When a stress fracture works its way across the bolt, it can be so small that it cannot be even seen with the naked eye. Rust will follow! How much corrosion takes place can be accelerated by salt air, or acidity from things like acid rain, water runoff through acid-charged soils (forest, etc.). Over-driven bolts in a hole that was not drilled deep enough in the first place will definitely cause stress fracturing. When holes are drilled into extremely hard, dense granite the holes will be just slightly tighter fitting, and the Rawl-Drive compaction bolt that is driven into that hole has to be hammered with even more force, - this could cause stress fracturing, too. For one thing, these compaction bolts were never designed for this type of application. Mostly, they were designed for concrete construction. When they are driven into concrete they never have to compact this tightly.

I started pulling the 5/16" bolts as well, as the 1/4" bolts, because I figured that these were oftentimes over-driven in their holes for the same reasons that the 1/4" had been. I started noticing what appeared to be some stress fracturing, with some rust through, on these bolts as well. These bolts just hadn't had the weathering, and age, that the 1/4" had had, because they had not started being made until perhaps 1986 or '87, I think.

I started seeing some of the 5/16" Rawl-drive that had the same problems as the 1/4" have. They just hadn't had time to rust as much. I did come across a few that snapped on me with that same sort of rusting that had gone through, and apparently weakened the bolt through a stress fractured area.

I've told many people about this time-bomb sort of feature, that is inherent in ferrous metal, and that was just waiting to happen. A lot of folks, for whatever reason, didn't seem to believe me on this subject. For one, they didn't really understand how I could pull a 5/16" Rawl-Drive button-head out, and because they hadn't been able to do the same, they figured that they were "way, way, bomber, man!"

But, like I have said, I really don't think anyone necessarily believed me anyway, and I'm talking about people that had a really good bunch of knowledge about bolts, and in some cases, re-bolting as well. 5/16" buttoned-head bolts were oftentimes so hard to drive into hard granite in the first place, then how could one possible pull it out, right? I remember saying to them, "Well, it's a time bomb just waiting to happen." It's just a real shame that a nice young man had to lose his life in order for there to be enough attention to be brought to the subject.

I'm not a metallurgist of any sort. I have studied, however, high school metal shops, and welding shops, as well as college courses in the same, and have had a long time interest in bolts and hangers and their applications.

jaaan

Trad climber

Chamonix, France

Mar 22, 2015 - 02:05pm PT

Thanks, Dimes - those shallow screw-expansion ones are skeeeetchy.

In fact those bolts were very common for over a decade (maybe two?) in Europe. There are still loads in use on French crags. They are the same as the ones I mentioned in the Caulking Bolts thread - see photos. These ones are 10mm but in fact we started off with 8mm being the norm.

I've never heard of any that have failed - though of course that doesn't mean there haven't been any. They have been systematically replaced over the years, at first with regular expansion bolts - usually 12mm in France, especially the south, and now the preference is for stainless glue-ins. Unfortunately in general the admirable US ethic of trying to re-use the same hole isn't even heard of in these parts. Sometime no effort is even made to remove the old bolt. Which is a shame...

m_jones

Trad climber

Carson City, NV

Mar 22, 2015 - 02:11pm PT

Another climb to add to the list with the 5/16 buttonheads is the AO on El Cap. Many in the belay bolts. We replaced a few to have at least one big bolt. I replaced an old 1/4 in a belay which came out way to easy and the other two were 5/16 button heads. Really glad I did now. Hauling puts a bit of stress on the anchors.

On the solo to set up a mini trac rope, I'd recommend using a set of aiders. Reach up with the stick and clip the aider into the bolt. Solo belay with the grigri as you would short fix and climb the aider up to the bolt. It is best if you can find an anchor at ground level or use the first and second bolt. Never stick clip anything by threading the rope up there and hauling yourself up with the rope.

two-shoes

Trad climber

Auberry, CA

Mar 22, 2015 - 03:21pm PT

jaaan said,"In fact those bolts were very common for over a decade (maybe two?) in Europe. There are still loads in use on French crags. They are the same as the ones I mentioned in the Caulking Bolts thread - see photos. These ones are 10mm but in fact we started off with 8mm being the norm."

I find this interesting, because I originally was a caver before I was a climber, and at the time we cavers were primarily using self-drive Red Heads that were basically a very similar design as these drop-ins.

I once talked to a construction worker who had worked on the Diablo nuclear power plant, and he was telling me that the Hilti drop-ins were the only bolt to come through all of the simulated earthquake testing they had done for many, various types of bolt designs that they were considering for okaying for construction of the power plant. This must truly be a design of bolt that could take repeated shock loads, and be able to hold in any pulling, or shearing direction, I would guess?

chappy

Social climber

ventura

Mar 22, 2015 - 04:16pm PT

Good call on your solo technique m_jones. If you clip your rope in first and then ascend it (as opposed to an aider)you double the load on the bolt (twice your body weight and any shock load you add by bouncing on it as you move upward). Bad! Don't do it the way the guy in Ben's photo a few posts earlier is doing it.
Chappy

surfstar

climber

Santa Barbara, CA

Mar 22, 2015 - 05:25pm PT

I've donated to the ASCA a couple of times, but would really like to buy those volunteers a beer or three to thank them. I much appreciate their work.

HighTraverse

Trad climber

Bay Area

Mar 22, 2015 - 05:53pm PT

RIP Scott
Hopefully as a community we can learn and then educate each other to help avoid the same fate.

A few scattered thoughts.
Most have already been stated but bear with me.

Redundancy
redundancy is our main concern with all anchors when we are climbing with a partner; traditional climbing. We make every effort to back up the belay anchor with 1 or even 2 redundant points. Even when the anchor looks "bomber". When we're leading we really don't want to fall with only one piece of pro.
Roped solo climbing while only running the rope through 1 anchor has no redundancy.
Roped solo climbing with always two connections for the rope has some redundancy.
Free solo climbing has zero protection (obviously)

Corrosion and stress cracking of steels are closely related.
The tensile strength of most ferrous metals (all steels) is significantly reduced by corrosion. This can cause micro crack initiation under stresses far lower than the design stress. Once a micro crack is initiated it will grow.
Driving a split bolt into rock stresses the steel and more importantly, the stress doesn't get relieved. It is permanent.
Micro cracks under constant stress will continue to propagate.
Tightening a bolt in rock with a threaded swage device at least controls the stress better than whacking the head with a hammer. OVER tightening the nut/bolt will increase the rate of stress cracking.

However note the critical parameters for stress cracking:

The difference in the diameter of the bolt and the hole. This is intuitively obvious as if the hole is too large there is NO stress on the bolt and it falls out. Consider that each bolt design is optimized for a particular hole size. Too large a hole and the bolt won't hold it's rated load. Too small a hole and the captured stress in the metal will be higher than the rated conditions. This will quicken stress cracking. The bolt is designed for a particular size hole.

- corrosion. This has three components: the specific chemical composition of the bolt, the amount of stress on the bolt AND the composition of any contaminants. Such as water. Or worse, water contaminated with acids or bases (depending upon concentration, temperature, steel composition etc either acids or bases can initiate or accelerate cracking).
Note that Mt Project specifically mentions water and bird poo on Life In Electric Larvae Land:

There is water at the base of this route and quite a bit of bird poo

And the rock itself is dyed with runoff from bird poo which is visible in the photo.
http://www.mountainproject.com/v/life-in-electric-larvae-land/107186124
And one more driver of corrosion: differences in metals which creates electrolytic junctions. All of the components in the bolt have to be selected as a system. It may be a bad idea to mix components from different manufacturers, especially if any of the component materials differ.

type of steel
Jeff Achey's article in Climbing has a couple of good paragraphs about this. Please note the Powers data sheet that was referenced earlier:
http://www.powers.com/pdfs/mechanical/06308.pdf
Zinc plated carbon steel is totally UN-acceptable for any outdoor Safety Of Life application. Any nick or scratch through the zinc will initiate corrosion in presence of (not distilled or pure) water.
So that leaves us with the significantly more expensive "Stainless" steels, 303 and 316. 304 is also common, particularly from Asia. 304 is much less "stainless" than 316
The quick takeaway is that for outdoor bolts only use 316 (the most expensive of course).

Examples: In corrosion sensitive (cosmetic or high stress) applications, high quality ship/yacht builders will never use 303/304 as it corrodes quickly in salt water/salt air. You can often spot "asian" 304 stainless steel in the sea side marina as it will not be as bright and after a few years will even develop patches of colored corrosion.
In the pharmaceutical industry the ONLY one of these we use is 316 as it has the highest corrosion resistance, but even it will corrode under some unusual conditions. We use even more expensive stainless steels for specialized applications. There have been some significant product recalls when an inadequate type of stainless steel was used in the manufacturing plant, or even worse in shipped products (304 is totally unacceptable for screws in orthopedic implants).

So the key variables we have control over:
For the bolter:

type of steel for the bolt, nut and hanger (cost)

size of hole

tightening torque

to a small extent, where we place the bolt. In a water smear is not a good idea if there's a suitable drier location. bird poop.....bad. mineral hot spring water....likely bad.

possibly sealant

A corollary: Non-stainless bolts in warm marine environments is about as bad as you can get. JTree bolts will likely last longer than Tuolumne Mdws bolts. A TM bolt in a water streak may not last as one nearby out of the water.

For the climber:

redundancy is the only thing we can do to increase our odds of success.

On Belay!

two-shoes

Trad climber

Auberry, CA

Mar 22, 2015 - 07:30pm PT

High Traverse, I concur with everything you've got there. It all rings of truth, I think. Good thought about the not using different metals in the system, - that's how you make batteries, right? I'm sure you re right about the stress fracturing occurring, in a wedge style bolt, depending on how tight the bolt gets tightened. I've wondered about this very thing as well. Perhaps, tightening the bolt just enough to lock the system is the most optimal? Totally agree with the redundancy system, too!

That makes me wonder about what type of stainless the common bolt hangers are made from. Shouldn't this be matched with the same type of stainless steel bolts, as well. What we need is a metallurgist to know how critical all of this might be given enough aging of the bolt/hanger system.

healyje

Trad climber

Portland, Oregon

Mar 22, 2015 - 11:09pm PT

I replaced 74 anchors up this way - most 5 piece bolts and out of 74 anchors both bolts where spinners in 58 of them. One bolt snapped under just the weight of the breaker bar, its mate with a 1/4 turn. I also checked every fixed pin on the face and either verified they were good, reset or replaced them. Overall, the pins far out performed the bolts even though they were placed in the 60s/70s and the bolts in the 80s/90s. In fact the 5pc bolts from the 90s were by far the worst.

The principle lessons I came away with were:

All fixed pro will eventually fail

All fixed pro requires checks/maintenance at some regular interval

You can't judge the current 'quality' of bolts or pins by the way they look

People seem to think bolts are good by default and it's someone else's job to replace them.

They aren't and it isn't...

Here's one of the few pins that looked great but weren't. It funked out with a slightest pull - no shortage of sh#t bolts that looked perfect either...

ß Î Ø T Ç H

Boulder climber

extraordinaire

Mar 22, 2015 - 11:31pm PT

I think of this case like a freesoloer death, cuz so sketch the means employed.

bhilden

Trad climber

Mountain View, CA/Boulder, CO

Mar 23, 2015 - 12:34am PT

Healyje,

I think environmental factors are a very important component in the longevity of fixed protection. One of the areas where I do a lot of rebolting, Pinnacles National Park, doesn't see a lot of moisture. The majority of the plated 5-piece bolts I have pulled have shown very little signs of rust or deterioration in quality.